Depends on which 911, but now with the power boost and the PDK, the base 911's power advantage is essentially gone. It is more balanced (Mid engine vs rear engine). Plus, it just looks so much better (no more porshe bubble-butt, and the new headlights on the '09 make it look even better. Motor Trend actually called it the best sports car in the world in their March issue
The 08 with a few mods will get to the same HP. The new DFI motor has stronger internals I've read then the 08's. But, as more people start racing the 06-08's aftermarket companies will make stronger internals to swap in.
The dealer I bought this from races a Cayman S. They have been quicker then turbo's on the track.