Autocar tested both the RS4 and M3. The big surprise was that both cars were so evenly matched, right up to 150mph the only thing that separated them was 0.3s. So even with identical power, more weight and quattro the RS4 was only 0.3s slower to 150mph.
What does that tell you about your opinion that quattro eats power?
If Audi are considering a RS6+ then the chances are they are safe guarding the fact that BMW will be upping the power of the M5, it's as simple as that.
I hope for your sake that the M5 is quicker because if not you WILL get some bashing from me, that's for sure.