2006 Audi RS 4 vs 2006 Cadillac CTS-v

Here's a List of features and components you get with Audi's raucous new RS, which aren't available on a Cadillac CTS-v: full-time all-wheel drive; direct fuel injection; Dynamic Ride Control; bi-Xenon headlights with automatic leveling, steer tracking, and retractable washers; 19-inch wheels and tires; rear and rear-side privacy shades; driver adjustable throttle-tip-in programming and exhaust system; aluminum hood and front fenders; cooled front seats and heated rear ones; and a lap timer.

And here's a list of what you can get with a Cadillac CTS-v: a Mini Cooper.

No, a CTS-v doesn't come with a new Mini in the trunk. But you could buy a loaded one for the $22,380 difference in the as-tested price between the $73,870 RS 4 and $51,490 CTS-v you see on these pages. Which puts two questions at odds with each other: Do you really get what you pay for, or can you get most of something elsewhere for less? We attacked our test track, some of Southern California's best driving roads, and our calculator in search of an answer.

What's the difference between Audi's S4 sedan and the new RS 4? Cojones, mostly. The "R" means that Audi has kicked it up a notch or three over the already sporty S. The RS 4 is a product of Audi's quattro gmbh, whichis, technically, a separate company (not to be confused with the name of Audi's all-wheeldrive system) that develops special models and is involved in other brand and lifestyle activities. Although somewhat different in function than BMW M or Mercedes AMG, the result in this parlance is the same: begin with a standard car and, in equal measure, amp up its performance, luxury, and exclusivity quotients.

Only the RS 4's roof panel and two front doors are from the A4. Audi V-8 models tend to be nose-heavy, as the engine sits fully ahead of the front axle line. Even more weight is added by the front-drive hardware. Thus, one goal for the RS 4 was to move the weight bias rearward, hence the above noted aluminum hood and front fenders, plus the relocation of the battery to the trunk. The front and rear fascias are aggressive, as are the curvaceous fender flares. Four large exhaust pipes poke out the back.

Although the RS 4's 4.2-liter engine shares its displacement and basic architecture with the S4's 340-horse V-8, it's in every other way a different powerplant, good for 420 horsepower-that's an 80-pony increase. Revisions to intake and exhaust systems, cam timing, and other components contribute, but the most interesting power-adder is direct fuel injection. Developed within Audi for its Le Mans-winning race cars, direct injection squirts the fuel straight into the combustion chamber for a more uniform fuel/air mixture. Thanks to the resulting cooling effect, the engine's compression ratio can be raised to 12.5:1. And it all revs to a Ferrariesque 8250-rpm redline. Acknowledging that Audi's DSG transmission is (so far) designed to work only with transverse engine installations, the RS 4 has a six-speed manual gearbox.

Ride height is lowered 1.2 inches, and all suspension tuneables are geared toward higher cornering limits and increased body control. in order to give more of a rear-drive feel, the Torsen differential allocates 60 percent of the power to the rear, instead of the previous 50. The S4's Dynamic Ride control system, which hydraulically connects the dampers diagonally across the car to reduce pitch and roll, has been retained. Aggressive 19-inch rolling stock is standard, as are full-floating, vented, cross-drilled fourwheel disc brakes, with the fronts employing eight-piston aluminum calipers.

A button on the center stack marked "S" gives you more aggressive throttle tip in (although no additional power) and opens up a baffle in each of the rear mufflers as well as a flap in the intake system. It's kind of like the "Loudness" button on a stereo - more volume and bass.

Inside, you'll find real carbon-fiber trim as well as well-bolstered Recaro seats trimmed in silky Nappa leather, although we don't get the more aggressive sport seats available on the RS 4 in other markets, and America's passion for cupholders has cost us the racy, console-mounted starter button. A moonroof is standard or can be deleted for those who want the slightly stiffer platform and reduced weight that comes with a solid roof. Whatever isn't covered in leather or carbon fiber is nicely finished in aluminum trim.