Last year, it appeared that Audi was playing out the ultimate April Fool’s joke. The German manufacturer agreed to deliver two of its most exclusive and adrenaline-inducing cars to our Malibu office for long-term evaluation on April 1. One of the vehicles was the mid-engine R8, which won over judges at Robb Report’s 2008 Car of the Year competition, and the other was the RS 4 Cabriolet—yes, a convertible. If it doesn’t sound familiar, that’s because Audi built only 300 units for the U.S. market in the 2008 model year, and then discontinued the entire RS 4 line (sedan, convertible, and wagon). On American roads, this particular sport-tuned model is rarer than the Ferrari F430, so the luxury auto brand’s decision to hand over the keys to two of their most enticing vehicles just seemed too good to be true. Thankfully, Audi is very serious about pushing its best sports cars into the media limelight, and is not in the business of pulling frivolous pranks.

Delivering these two cars into the hands of Robb Report’s editorial staff on the same day was a tactical move on Audi’s part. Although the R8 and the RS 4 Cabriolet appear to be polar opposites from the outside, the models sport a couple similarities: both are powered by a high-revving 4.2-liter FSI V-8 engine, both come standard with Audi’s phenomenal rear-biased quattro all-wheel-drive, and their performance figures are staggeringly close. Both cars produce 420 hp at 8,000 rpm, so it’s no surprise that the RS 4 Cabriolet is not even half a second slower than the R8 to 60 mph.

The real difference in performance becomes apparent on curvy roads: The R8’s low-slung stance and mid-engine layout help it hug every corner, while the RS 4’s structural rigidity is clearly compromised by the lack of a solid roof. Although the cabriolet’s handling is extremely impressive for a soft-top convertible, many of our editorial staff found the Pacific Coast Highway a much more fitting environment for the RS 4 than the countless canyon passes near our Malibu office. Even then, those looking to simply cruise were disappointed to discover that Audi only produced the RS 4 Cabriolet with a manual 6-speed transmission. More intrepid staff members, like Don Williams, the former senior editor of Robb Report MotorCycling, took up the challenge to seek out roads that complemented the RS 4’s real strengths: "Highway 58 from Santa Margarita to McKittrick, in California, is made for this car. High-speed bends, straightaways, elevation changes—whatever you want, it’s there. The shifts are smooth and simple, and the handling is simply spectacular. The car settles into turns, with quattro making short work of unexpected turns. Continental tires and stiff suspension cover every portion of asphalt without the slightest drama."

The only members of our staff who really experienced any sort of drama in the car were rear-seat passengers. The 30-minute car pool from Santa Monica left many editors, who attempted to hold conversations with front-seat occupants from the back, feeling a bit unprofessional around the office with unkempt hair and worn vocal chords.

Unfortunately, strained voices weren’t the only things that wore thin from excessive top-down motoring. After the summer months, the light-gray leather seats—which looked fashionable when the car was new—became dingy, and eventually just a few shades away from black. Editors quickly learned that a weekly detailing was necessary to keep the grime at bay.

Despite the impractical color choice, the RS 4’s interior still impressed staffers. Drivers found that the familiar center console made for simple adaptation and menu navigation, and they liked the convenience of the single button on the driver’s-side door to simultaneously raise or lower all four windows. Users also favored the elegant carbon-fiber trim accentuating the dash and doors, the individual seat warmers, and the climate memory system that automatically changed the A/C or heat settings when the top was up, and then again when it was down.

The ragtop, which folded into its rear compartment in 24 seconds, left enough space in the trunk for two weekend bags when it was stowed. Open-air motoring was the preference for many of our editors during Malibu’s seemingly endless summer; thankfully, this mode of travel also improved the clean exterior lines of the car.

The RS 4 Cabriolet does not share the same aggressive proportions as its sedan-model sibling, and with its soft, rounded body panels, it is nowhere near as menacing as the Audi R8. But the R8 is an anomaly among the Audi family of vehicles. Study the company’s portfolio of cars, and it becomes apparent that the brand is more interested in producing understated performance monsters than flashy exotics. The Lamborghini-derived engines of the S8 and S6, and the twin-turbocharged 580 hp RS 6 wagon, immediately come to mind, but the RS 4 Cabriolet still stands out among the rest because of one especially rare feature: its ragtop.

The RS 4 was the only RS model that was offered as a convertible variant, and the only Audi—aside from the 1984 Sport Quattro—built in such low numbers. For these reasons, the Cabriolet came with a price tag of nearly $85,000 (after gas-guzzler tax and destination charges), which is a premium of more than $15,000 over the standard RS 4 sedan. Audi did not build this car to everyone’s tastes, but anyone who enjoys the rush of wind, the sound of a big V-8 engine, and the element of extreme exclusivity will understand why the RS 4 Cabriolet is the real deal. The notion of a soft-top performance Audi is not a joke, and those willing to seek out one of the few models on American soil and pay for the privilege of ownership will undoubtedly sport a smile on sunny days.