• Apr 24, 2009
Subaru Forester XTI concept, WRX and STI with SPT mods – Click above for high-res image gallery

Subaru invited us out to the track to sample some of its Subaru Performance Tuning (SPT) components, fitted to the company's Forester XTI show car, as well as the Impreza WRX and STI models. While we applaud any manufacturer that engineers a line of factory-approved aftermarket parts, we hand out additional kudos to the few who welcome us to a local racing circuit to put them to the fire. What add-ons did Subaru bring to Willow Springs, and how did they perform on the track? Come with us to find out...



Photos Copyright ©2009 Michael Harley / Weblogs, Inc., Subaru North America

Subaru STI Performance Parts are found in a glossy 18-page catalog chock-full of short throw shifters, strut braces, exhaust systems, cold air intakes, transmission mounts, boost gauges, and more. Of course, one will also find the obligatory cosmetic carbon fiber add-ons, STI mugs, and Subaru-branded golf balls. While most of the parts are covered under the factory limited warranty, some of them are only covered under the limited parts warranty, and a few are sold "as-is" without any warranty covered (those are typically designed for "off-highway" or race applications only).



To give us an excellent back-to-back comparison between a stock and an SPT modified vehicle, Subaru brought four cars to the Streets of Willow Springs race track, located just outside the town of Rosamond in the California desert. There were two Impreza WRX models (one stock and one modified), and two Impreza WRX STI models (one stock and one modified). As an unexpected cherry on this ice cream sundae of an afternoon, Subaru also brought out its one-of-a-kind Forester XTI concept for its track debut. That's right, the SEMA show car custom-fitted with full STI running gear!

2009 Forester XTI (Concept)

  • 2.5-liter turbocharged boxer flat-four
  • Est. 315 hp / 300 lb-ft
  • Six-speed manual
  • Dunlop SP Sport 600 – Max Performance Summer Tires (200 A A)


As a one-off concept, we were understandably apprehensive about tossing this particular Forester into the corners at speed. To our amazement, however, it handled the circuit like a true champ. Entering the turns, the compact SUV displayed initial turn-in that inspired confidence (the underpinnings are slightly modified from the STI, not mirrored). While credit may go to the additional weight over the front end, that same mass becomes a slight penalty while exiting the sharper corners which took all 315 horses to get back to speed. We didn't push it that hard, but overall the XTI was balanced and easy to drive without any glaring shortcomings. Subaru's so-called "tarmac monster" delivered as promised. Now, we want to see it in the showroom!

2009 Impreza WRX four-door sedan (stock)
  • 2.5-liter turbocharged boxer flat-four
  • 265 hp / 244 lb-ft
  • Five-speed manual
  • Dunlop SP Sport 01 – Ultra High Performance Summer Tires (280 A A)


While the bone-stock Subaru WRX is a ton of fun as a daily driver on public roads, but when the new body style debuted, it simply became too domesticated for proper showroom-to-track duty. In fact, its inadequacies – starting with the suspension – surface in the first corner. When really pushed, the tallish ride height leads to pronounced body roll. The stock WRX suspension is soft and the body tends to float rather than settle down. The shift in weight unloads the inside tires and strips them of their contact patches. Pushed harder, the stock WRX will plow as the front outside tire is completely overworked. Adding power simply increases the tire howl without any significant directional change. Lacking firm suspension while sliding on street tires, the best way to recover is to get off the gas, wait for the vehicle to dump weight back on the inside springs, and then use the all-wheel drive grip to hustle the car around the corner. Driven at 8/10ths, and with weight transfer a mental priority, the stock WRX is safe and predictable... just not a slot-car ride on a track.

2009 Impreza WRX Five-Door
(SPT modifications)
  • 2.5-liter turbocharged flat-four boxer
  • 265 hp / 244 lb-ft
  • Five-speed manual
  • Dunlop SP Sport 01 – Ultra High Performance Summer Tires (280 A A)
  • STI Lip Spoiler
  • STI Shift Knob 5MT
  • STI Short Throw 5MT
  • STI Shifter Bushing
  • Strut Tower Brace
  • Chassis Brace
  • SPT Performance Exhaust 5D


The stock five-speed transmission feels great... until you try the short throw set-up. Then, you quickly realize how much it improves shift throw and feel without adding unnecessary effort or making the transmission feel too mechanical. We like it. Under the skin, this WRX is fitted with chassis reinforcements, but really no other suspension modifications. It also wears a throaty SPT stainless exhaust system. There must be some "mental horsepower" with the new exhaust, because the aggressive sound caused us to push this car much harder than the stock WRX on the track.

Seat of the pants, the chassis did feel a bit better, but lacking any direct suspension upgrades we found ourselves plowing and sliding into the corners yet again. Interestingly enough, something else surfaced: Driven at 9/10ths, our higher speeds were really starting to destroy the single-piston brakes. The stock pads were overheating and the rotors were getting chewed-up. Even worse, we noticed that heavy brake applications above 90 mph would invoke immediate ABS. With the wheels clawing for traction, the WRX would become uncomfortably unsettled on the stock suspension. While the short throw shifter and new exhaust was welcomed, we think the chassis-bracing modifications were a bit out of order – our money would focus on calming the struts, sways, and springs first, along with a new set of brake pads.

2009 Impreza WRX STI five-door
(stock)
  • 2.5-liter turbocharged flat-four boxer
  • 305 hp / 290 lb-ft
  • Six-speed manual
  • Dunlop SP Sport 600 – Max Performance Summer Tires (200 A A)


The stock STI was immediately a noticeable improvement over both WRX models. With additional power, a more advanced AWD system (including the Driver Controlled Center Differential), and Brembo brakes, we were able to push it hard on the track. In stock showroom form, the high-performance STI still exhibited noticeable body roll and would eventually understeer, but after a few laps, it became easy to predict exactly how the vehicle would react. While we were absolutely killing the stock street tires, and the brake pads weren't up to heavy track duty, it was apparent that your Average Joe could hit the local circuit in a stock STI and spend his day plastered with a big grin.

2009 Impreza WRX STI five-door
(SPT modifications)
  • 2.5-liter turbocharged flat-four boxer
  • 305 hp / 290 lb-ft
  • Six-speed manual
  • Dunlop SP Sport 600 – Max Performance Summer Tires (200 A A)
  • STI Lip Spoiler
  • STI Shift Knob 6MT
  • STI Short Throw 6MT
  • STI Shifter Bushing
  • SPT Strut Tower Brace
  • SPT Chassis Brace
  • STI Pink Springs
  • SPT Performance Exhaust System 5D


What a difference some good suspension tuning makes. This STI was fitted with the 6MT short-throw shifter and stainless exhaust. Both are must-have items that really complement the personality of this high-performance vehicle without sacrificing ride quality or comfort. Under the skin, the modified STI was equipped with chassis braces and new springs, lowering the ride height and firming things up.

On the race circuit, this STI was clearly top dog. It was incredibly stable in the corners – almost neutral – and we could really use its power to our advantage on the exits. Again, the tires and brake pads were the weak links, but those are both easy aftermarket fixes. This STI was outfitted very well for a combo daily driver/track role, as it never felt abusive or harsh in our hands (as dedicated track cars often do). With a set of R-compound tires and some race pads slipped into the meaty Brembo calipers, a vehicle configured like this STI would eat more than its share of competitors on the race circuit.



Bred on the competitive World Rally Championship circuit, the WRX and STI both offer an impressive amount of street performance straight out of the box. The track is a whole different animal, as was evident by the abuse the street tires and brake pads were taking on all of the vehicles (if you are going to regularly track any vehicle, do yourself a favor and invest in the proper tires and pads first). Competition consumables aside, there are countless aftermarket options when modifying an Impreza. And with factory engineering and designs proven in professional racing, Subaru owners would do well to check out the comprehensive list of SPT offerings.



Photos Copyright ©2009 Michael Harley / Weblogs, Inc., Subaru North America


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    • 1 Second Ago
  • 33 Comments
      • 5 Years Ago
      Note to Subaru: BRING THE XTi!
      • 5 Years Ago
      Car and Driver had a blurb a few months back about a school swapping the MS3 drivetrain into a 5. the 5 is a good mini-minivan, almost like the pacifica with it's 2+2+2 seating, but just looks too pontiac transport-ish for me still.
      • 5 Years Ago
      that was supposed to be @Tomac.

      Dear AB, please update so we can edit and move our posts.
      • 5 Years Ago
      That Forester is badass.
      • 5 Years Ago
      I was really close to getting an STI, but then decided on an '09 Mazdaspeed 3. It was just the better choice considering the roughly $15,000 price difference. So far, I love the MS3 and will probably leave it bone stock...its plenty fast and handles great. If I want, I can perform a couple mods from Cobb Tuning and get STI type performance out of it...probably for under $2K. I don't think there is any better performance bargain on the market than the MS3.

      Now, if I had to do it over again...and the economy were doing better... I'd probably go with a 370Z....love that car.
        • 5 Years Ago
        ditto on the 370Z

        but the MS3 will always suffer to the STi as the AWD system makes the STI a monster in any weather - bar none. but it's too ugly to be my ride even so.
        • 5 Years Ago
        cobb cobb cobb
        AP tuner, SRI and cat-back.

        the AP tuner can remove the boost cut and increase boost (besides other things like timing and fuel trim). AP tuner also includes low-boost and valet modes, which might be useful for city driving.

        Cobb is known for their suby work too, so this isn't completely irrelevant
        • 5 Years Ago
        15k price difference? I got my 08 STI for 27k, just about 30k OTD. new. With 0% financing for 63 months.

        I was eyeballing the MS3 for half a year as the STI was way out of my price range...Sometimes it pays to wait :)
      • 5 Years Ago
      "xtasi said @ 12:14PM (4/24/2009)

      So, I need 300+ hp for going to work, in traffic???? and the trick SI drive? must help a lot in stop and go traffic."

      Typical nonsense. You don't get it and never will. Keep driving your appliance and STFU on sports car blog posts. I take great pleasure getting around dumb fks like you who insist on riding in the left lane with no one ahead of them. I especially love when they even try to attempt to close the gap when they see me coming and fail miserably as my tuned > 310 WHP beast slides in front of their stupid arse.
        • 5 Years Ago
        Way to be a reactionary schmuck! Congrats on your internet slam, though it suggests that you score low on reading comprehension. If you read the FIRST part of the post, it's more a complaint about Subaru touting their rally heritage and (at least theoretically) penalizing people who actually take their cars to the track, since many the cars are so close to track-ready with very light modding.

        But I'm sure you enjoyed your "win" by slamming him, just like you do when you cut people off in traffic.
        • 5 Years Ago
        Also, you sound like a very balanced and mentally stable driver. Yeah right. You sound more like a ricer.
        • 5 Years Ago
        You /really/ missed the point, Threader.
      • 5 Years Ago
      Shoot me for not being on top of this, but isn't there a SoCal outfit (or two) that regularly trumps anything that has been offered by SPT?
        • 5 Years Ago
        Perrin, Cobb, Cusco, AVO, and I am sure there are many others.
      • 5 Years Ago
      Too much Subaru goodness...
      • 5 Years Ago
      Subaru, bring the Forester XTi!!!! It's a Cayenne S at half the price, without the dodgy reliability. I can haul my kids and haul ass. And in all weather. This would be the ultimate no-compromises vehicle. Sign me up!
      • 5 Years Ago
      Mechanically they're solid machines and performers, and I'm sure the higher end versions are amazing to drive, with the exception of the previous gen Legacy, their designs completely lacks any character. Even the Corolla has more design personality inside-out.
        • 5 Years Ago
        I feel the same way about Audis.

        Compared to many other autos (especially from Japan) I'd have to wholeheartedly disagree about Subarus. Most Japanese cars tend to look like generic appliances (though the new Mazda3 looks like an appliance with a smiley face) ~ this looks like a Subaru: funky, European meets Japanese exterior. Looks all business to me (especially the STI). The 5-door is one of my favorite hatches on the road. You want boring? Take a look at the GTI. I would definitely take a Corolla over a Rabbit, no doubt.

        I'm not seeing what you're talking about with the Corolla compared to the WRX/STI. Perhaps you're a Toyota fan?
      • 5 Years Ago
      Ooh that Subaru Forester XTI Concept is hot. I'll take one!
      • 5 Years Ago
      Not only is the Forester XTI badass, it is brown, making it doubly badass.
        • 5 Years Ago
        More brown cars!
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