While no official details have been confirmed it is rumored that Audi will most likely fit the RS 5 with the same 420 horsepower V8 engine from the RS 4. Even better, Road&Track sources are saying that Audi may even look to fellow Lamborghini for the 5.2 liter V10 engine that produces 500 horsepower in the Gallardo. That should definitely leave the M3 in the dust.
Whatever the case, Audi will fit the RS 5 with Quattro all-wheel-drive and most likely offer big arse Brembo brakes. The body will take on a much more aggressive look than the S5 along with a sportier interior.
Source: EGM Cartech