For 0-60 times, low end torque and traction is more important than all out engine power.

997's 3.8 engines produces about 220lb-ft at 1500 rpm, that's around/just over the threshold for 2wd's weight advantage over awd, so the awd versions gets to 60 faster.

The 4.5 V8 produces almost 300lb-ft at 1500rpm, so awd is definitely an advantage for acceleration from stop.