Vital Stats

Engine:
Twin-turbo 4.4L V8
Power:
542 HP / 587 LB-FT
Transmission:
8-Speed Auto
0-60 Time:
4.0 Seconds (est.)
Top Speed:
190 MPH (est.)
Drivetrain:
Rear-Wheel Drive
Curb Weight:
4,400 LBS
Seating:
2+3
Steve Dinan has been enhancing BMW models since 1979. But don't throw his company into the ring with the dozen or so other tuners who tweak, tinker and piggyback upgrades on the famed German marque. Dinan is a tuner, but it's also an engineering firm that writes its own software, builds its own parts and then backs everything it does with a factory-grade warranty. That sort of fastidiousness comes at a price, but most of its customers – including the powerhouse of BMW Motorsport – rely on Dinan to help them come out on top.

In stock form, BMW's 550i is a formidable four-door with a twin-turbocharged 4.4-liter V8 rated at 400 horsepower and 450 pound-feet of torque. While those figures allow it to run with quick company (0-60 in 5.0 seconds, according to the automaker), Dinan puts the sedan's kettle on full boil with its S3 package. Starting with the engine, the performance engineering firm bolts on larger turbochargers, air-to-water intercoolers, a trick strut tower brace cold air intake, a quad-pipe free flow exhaust and its own engine management software. Pump in some premium fuel, and the result is 542 horsepower and 587 pound-feet of torque. Power is sent through the stock eight-speed automatic to a limited slip rear differential (Dinan will upgrade xDrive all-wheel drive models, too).

The Dinan S3 also features and extensive suspension upgrade that includes new front camber arms and low compliance rear control arms (engineered to reduce understeer and improve turn-in). The stock dampers are retained, but new bump stops are installed along with new springs. Overall, the car rides about a half-inch lower than stock to improve roll rate. To reduce unsprung weight, forged 20-inch HRE Performance wheels are fitted at all four corners (wearing Michelin Pilot Super Sport tires - 275/35ZR20 up front and 295/35ZR20 in the rear). Lastly, the company remaps the factory Electronic Damper Control (EDC) software with its own Dinan Shockware to work in conjunction with the new enhancements.

The base price of the 2013 BMW 550i is $62,625. Add another $38,773 for the full complement of Dinan upgrades on our test vehicle, and the BMW Performance carbon fiber body components. Expensive, but withhold your judgement until after you've stepped on the accelerator pedal.

Driving Notes:
  • Without a doubt, the Dinan engine package is the most seamless aftermarket upgrade I have ever experienced. The impressive increase in power is velvety smooth and natural in its delivery, devoid of the negative characteristics (hiccups, peaks and flat spots) that are common to most other tuned vehicles. The 550i lacks launch control, so the twin-turbo S3 requires a delicate right foot, or the rear tires quickly liquefy. Drive it properly, with a light touch followed by heavy throttle a few feet off the line, and the sedan takes off like a missile - quickly embossing your spine into the leather seatback. The smooth ZF eight-speed shifts with authority, yet without any of the harshness normally found with a dual-clutch. Dinan doesn't publish acceleration figures, but my tuned derrière dyno says it slices upwards of a second off BMW's published 550i time to 60 mph... and it runs unrestricted to over 190 mph.
  • Dinan touts its S3 550i as "a more luxurious version of the M5" with softer shocks and active roll control that give its car the edge when it comes to ride quality. They aren't fibbing, as the enhanced 5 Series provides a very comfortable ride when the EDC is set in Comfort, and sharp response when configured in Sport and Sport Plus. There is less understeer, thanks to the new camber and control arms, and nothing seemed to unsettle the chassis. The stock adaptive suspension worked seamlessly with the physical and software upgrades - the wide range of suspension settings was impressive.
  • If asked what I didn't like about the augmented 5 Series, I'd have to mention the steering. Three years ago, when I reviewed the BMW 550i, I commended the steering's accuracy but complained about its numbness and isolation. That said, Dinan doesn't touch the electric steering, so don't expect it to be improved. Again, this is more of a wish for improvement than a deal breaker.
  • Dinan's superb S3 BMW 550i obviously competes nearly directly with the factory's own flagship M5. In terms of power output, the Dinan feels every bit as burly as the 2013 M5 (keep in mind that BMW boosted performance of its M5 for the 2014 model year with the optional Competition Package), but its personality is softer and bit more tame - less high strung would be another good description. Both are excellent examples of the 5 Series. However, if asked which one I prefer, I'd select the hardened M5 for competitive track events but choose the polished Dinan as my daily driver. Where do you spend more of your time?


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    • 1 Second Ago
  • 37 Comments
      Jonathan Wayne
      • 1 Year Ago
      Pass, rather have the M5. Factory with better looks and amenities inside and out than this car.
      domingorobusto
      • 1 Year Ago
      I kind of love the sedate styling. Nothing better than a sleeper in my book. Although I'd take one look at the seriousness of those brakes and wheels and instantly stop thinking that was a sleeper. Sounds like every Dinan product though. Extremely well executed but incredibly overpriced.
      Matteo239
      • 1 Year Ago
      587 pound-feet of torque :)
      RetrogradE
      • 1 Year Ago
      This car is like my wife: 1. A little on the plain side, but can really motor. 2. Costs me a little more than I really want to pay, but in the end, see #1.
      sp33dklz
      • 1 Year Ago
      It\'s still a porker. No thanks.
        RJ
        • 1 Year Ago
        @sp33dklz
        Jaguar XJ AWD Audi S6
          Michael Harley
          • 1 Year Ago
          @RJ
          Good call on the aluminum Jag at 4,150 pounds (but few put it in the same category as the M5/CTS-V/S6/E63). However, the S6 is 4,400 pounds... just like the Dinan. - Mike
      E85 450HP Forester
      • 1 Year Ago
      I was excited at first but then curve weight at 4400lb..:(, hard to believe my grocery getter Lesbian preferred wagon has a better power to weight ratio: 3000lb/450HP = 6.66, vs S3 Dinan 4400lb/542HP = 8.11, that is 22% better,
        AcidTonic
        • 1 Year Ago
        @E85 450HP Forester
        No one cares here..... this is the "buy it" crowd. They don't like "build it" guys like us who add 100hp or more to their car . We are "niche" market buyers and we don't matter. (until of course we tell our close friends and family who trust us, what is good and what isn't.... then it's "sales data").
          • 1 Year Ago
          @AcidTonic
          [blocked]
          • 1 Year Ago
          @AcidTonic
          [blocked]
        The Wasp
        • 1 Year Ago
        @E85 450HP Forester
        The Forester is a crossover...don't be afraid to call it what it is.
          E85 450HP Forester
          • 1 Year Ago
          @The Wasp
          huh? idiot not all Foresters are created equal. http://www.google.com/imgres?imgurl=http://media.caranddriver.com/images/media/108201/2007-subaru-forester-25xt-photo-131916-s-1280x782.jpg&imgrefurl=http://www.caranddriver.com/photos-07q2/108201/2007-subaru-forester-25xt-photo-131916&h=782&w=1280&sz=110&tbnid=JQ0zJniWogzNsM:&tbnh=74&tbnw=121&zoom=1&usg=__0ZcrFrG3ETTAzs2KK4t5pFkIIWc=&docid=dBHoaNDrkuDfcM&sa=X&ei=ELSoUaOFLoaY9QT53oC4Dg&ved=0CDkQ9QEwAQ&dur=332
      mbukukanyau
      • 1 Year Ago
      I hope the V sport can out run this thing bone stock.
      Thipps
      • 1 Year Ago
      Just cant get over the hood cut lines. SO not BMW. they are detail and attention freaks i just dont see how this got past them. I mean the chevy Malibu has nicer cut lines...yikes
      vroooomy
      • 1 Year Ago
      so just get a M5?
        RetrogradE
        • 1 Year Ago
        @vroooomy
        HELLA. Even a used E60 M5 will only cost you mid-$30K at the most.
          • 1 Year Ago
          @RetrogradE
          [blocked]
        • 1 Year Ago
        @vroooomy
        [blocked]
        Dvanos
        • 1 Year Ago
        @vroooomy
        I agree, especially for $110k.
      Mondrell
      • 1 Year Ago
      "I'd select the hardened M5 for competitive track events." Often as I tend to take a liking to cars that raspberry the laws of physics, I wouldn't pick either for track events. Too heavy and in the case of the M5, less effective than its spec sheet suggests. M3s or CTS-Vs can keep pace while providing far more involvement. Within the same class, the E63 4Matic will likely crush it by virtue of actually being able to put the power down.
      Dvanos
      • 1 Year Ago
      In before all the "bland" styling comments.
      Scooter
      • 1 Year Ago
      In-house tuner garbage. Sorry to say it. Take an unrefined hunk of a car $40,000 later. You get $100,000+, 5 second car. Purely a collector car that's easily bested by $40,000 cars.
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