For the swappers-S6 engine

[TM]

I don't know about the 3.6L engine, but the current 300hp 4.2L 40v
motor is very nice indeed. In the A6 4.2, the car moves with authority
and doesn't feel like it is lacking in torque. Unfortunately, with
the Tiptronic, it starts in 2nd gear, so it doesn't really boot off
the line- I'd like to drive one w/ a 6-speed just to see what its true
potential can be.

However, as you mention, there isn't a whole lot more you can do with
the engine- the S8 40v is at 360hp. Maybe custom tuned-length headers,
full dual exhaust w/ x-pipe, port and polish, that's about it. I speculate
that you'd be hard pressed to extract more than 400hp out of the S8
engine w/o forced induction or displacement increase.

The M5 5.0L engine has the torque and power that you're looking for,
but that may be due to the larger displacement as well as the manual
transmission's more direct feel.

Still not as tuneable as a turbo engine and lousy at altitude, as our
CO listers can attest.

Taka