Go with the Audi. I've been eyeing those for a while now.
As for the Mazdaspeed6, I just wish they put a real engine in the car. It looks like they're doing so much else right with that car, then they throw in a turbo 4. In all, they're moving their cars in the right direction, but they still leave a little to be desired.
They're trying to cash in on the WRX/EVO thing, which doesn't fit that car. The new 2.3L 4 is great, but Ford has so many other engines. I'm sure they could get more out of the 3.0L Duratec too. Hey, why not try the new 3.5L Duratec?
The engine is the weak link in an otherwise awesome chain, and therefore, the Audi gets the nod.