This more dramatic driving style will reveal an attitude problem from the stick, which tends to get cranky when handled with urgency. BMW uses a multi-disc clutch system to split torque between the left and right rear wheels, transferring up to 100 percent to the one with grip. Damping is variable and can be adjusted automatically (or according to the driver's preference) from the EDC's three-option menu: Normal, Comfort and Sport.
Next to this button there is another command that disengages the stability program, an option also available in the Audi (either totally off, or with the traction control still in surveillance mode). Altogether, this fourth-generation M3 proves to be less intuitive to drive, it takes a bit more homework, but it also allows the driver to store his choices and execute them with a touch of the iDrive button set into the steering wheel. Pressing it makes the car's character go from 'traction-controlled, light-steering and comfortable' to 'brutal, hard-riding, wheel-spinning racecar' as well as all the other possibilities in between these two extremes.
It's a different ball game in the Audi. In everyday circumstances, 60 percent of the goods are delivered to the rear wheels. But a fluctuation of grip conditions between the two axles can change that to 15/85 percent or 65/35 percent, all courtesy of a Torsen limited-slip differential. The RS4 also relies on a mechanical solution for variable damping, included with this sport suspension package. An S button on the steering wheel spices up throttle response and tightens the lateral support in the driver's seat. It's easier to go really fast with the Audi, especially so in slippery or wet conditions where the all-wheel drive becomes a guardian angel. But even on twisting, full-grip mountain roads, it's clear that not only the response of this direct injection V8 is more emphatic, but also the steering seems to be more communicative (despite BMW's sophisticated steering potentially adjusted to the driver's preferences).
Braking is vital in these machines, but neither of them feature ceramic brakes (Audi offers them as an option; BMW could well be saving them for the probable, harder-core CSL version). While the stopping hardware handles daily needs neatly, the Nrburgring addict will have to sacrifice every third lap to recover from fade brought about by intensive use.
The M3 has an altogether more bourgeois pose when put alongside its predecessor and only shows full rage at the top end of the rev counter. In this rarefied environment, the experienced driver will have loads of adrenaline (after shutting down the electronic stability program) and will probably be able to outpace the RS4. But clearly, that will not be the case with the 90 percent of drivers for whom going Quattro means going faster.
2008 BMW M3
Longitudinal front engine, rear-wheel drive
4.0-liter V8, dohc, 32-valve, double VANOS valve timing
MacPherson struts, coil springs, anti-roll bar (f), multi-link system, coil springs and anti-roll bar (r)
Ventilated 14.2-in. cross-drilled discs (f), ventilated
13.8-in. cross-drilled discs (r)
*Wheels and Tires
8.5x18 (f), 9.5x18 (r)
245/40 ZR18 (f), 265/40 ZR18 (r)
Length x Width x Height (in.):
181.7 x 71 x 56.1
Wheelbase: 108.7 in.
Curb weight: 3641 lb
Peak power: 414 hp @ 8300 rpm
Peak torque: 295 lb-ft @ 3900 rpm
Top speed: 155 mph (limited)