The Audi RS5 is a bit of an odd duck in the brand's US lineup. At the moment it is one of only two RS models – the other being the TT RS – atop a pyramid of A and higher-performing S models. It is not, however, the brand's flagship performance model – not even close – that space being occupied by variants of the R8 supercar, specifically the V10 and GT models, and upcoming 560-horsepower RS7.

The RS5 does, however, owe its beating heart to those ten-cylinder R8s, its own 4.2-liter V8 almost identical to those engines save for two fewer cylinders. Outside of the R8, then, the RS5 is the lone bastion of naturally aspirated V8 power in a brand that once happily shoved 4.2-liter V8s under any hood that they would fit. Today, not even the giant Q7 SUV offers a V8. Lastly, the RS5 is not new, except to us, having been on sale in Europe in coupe form the last couple of years.

While Europeans were able to enjoy the hardtop two-door without us, the RS5 Cabriolet is reaching both peoples around the same time: now. We reviewed the RS5 coupe just recently, and having spent some time with the tin-top model myself as well, here is my take on the droptop version of what I consider one of Audi's most interesting models.

Driving Notes
  • West Coast Editor Michael Harley likened the RS5 coupe to a supermodel. The metaphor survives intact when driving around with the RS5 Cabriolet's top down – it's like walking around town with a topless supermodel on your arm. The attention this car receives is surprising considering most people don't blink twice at a standard A5 or S5. I received thumbs up, waves and shout-outs from kids on bikes, one grown man in an Escalade and an entire Burger King cook staff.
  • This can partly be explained by the RS5's aggressive styling accoutrements that include wider fenders; 20-inch wheels housing attention-grabbing "wave" rotors; a giant, single-frame honeycomb grille; oversized air inlets and a noticeable rear diffuser. The other reason is that it's rare; only 1,200 RS5 coupes have been sold in the US since last summer, and the Cabriolet has only just arrived.
  • Some argue that the RS5 isn't worth the extra $18,000 over the cost of an S5. The RS5 Cabriolet doesn't help itself in this regard with a base price of $77,900 – some $18,600 more than an S5 Cabriolet. This one was loaded up with the optional Estoril Blue crystal effect paint and black roof ($1,075), MMI Navigation plus package ($3,450), Driver Assist package with adaptive cruise control, dynamic steering and side assist ($3,250), Sport exhaust with black finishers ($1,000), 20-inch five-spoke wheels with summer tires ($1,000) and Matte-Aluminum Optic package ($750) for a grand total $88,425, not including an $895 destination charge.
  • I don't buy the above argument that the RS5 fails to justify its price premium. That's what people who reach to afford an S5 tell themselves, and they're right in that case: Settling for the S5 is smarter than raiding your retirement account for the RS5. But the RS5 is the better of the two, and if the $18k difference between them is less than a rounding error on your tax refund, then pay Audi's premium for owning the best and enjoy.
  • I would reach to cover that $18k difference just to own one of the last and best examples of Audi's amazing 4.2-liter V8. Variants of this eight-cylinder have occupied engine bays all across the Audi and Volkswagen brands since the early '90s, but are now being replaced by a supercharged 3.0-liter V6 and, when more power is needed, a twin-turbo 4.0-liter V8. The two remaining 4.2-liter V8s belong to the R8 and RS5, though they're far from the same engine. From what we've been able to cobble together of Audi's engine lineage, the R8's standard engine is a high-revving version of the 32-valve V8 that was initially used in the Q7. That engine was eventually upgraded with more advanced mechanicals and engine controls and modified to become the 5.2-liter V10 used in the last generations of the S6 and S8. The RS5's 4.2-liter V8 is a version of that V10 but with two fewer cylinders, making it closely related to but more advanced and powerful than the R8's older 4.2-liter V8.
  • This engine revs like something with four fewer cylinders, which is fortunate considering how many revs are required to reach its high-for-a-V8 redline of 8,500 rpm. With all 450 horsepower not fully realized until 8,250 rpm and just 317 pound-feet of torque available from 4,000-6,000 rpm, you'll be working the 4.2-liter V8 hard to enjoy its full potential, but it's worth it when you hear the optional Sport exhaust system's baffles barking with every downshift in Dynamic mode. When not being worked, the RS5's engine reveals its ancestry as a luxury motor, quietly and effortlessly going about its job.
  • I generally prefer coupes to convertibles, but the RS5 Cabriolet is an effective champion of topless motoring. Raising and lowering the roof is a simple single-button affair that takes no more than 20 seconds to go up or down and can be done while on the move at low speeds. A separate button, meanwhile, raises and lowers all of the side glass. The situation that won me over was cruising along a two-lane state route after the sun had dipped below the horizon but the air was still warm in the breeze. Messed up hair be damned, that was fun. While wind noise was obviously higher with the roof stowed, I was still able to carry on a phone conversation over Bluetooth.
  • Would I choose the RS5 Cabriolet over the RS5 coupe? Sadly, no. While I would happily pay for the joys of the RS5 over the more affordable S5, the $9,000 premium required for the convertible is one that's too dear considering my proclivity for coupes. That, however, is a subjective judgment call we all make when faced with the decision of coupe or convertible. The real question lies outside the Audi fold, where BMW and Mercedes-Benz offer equally compelling, powerful and expensive convertibles.