I'm riding a P2-- I can't justify the $4800 for the P4 frameset because I have some training to do--that's good for about 10 minutes on the bike leg, and all it costs is a little pain.

But yeah, if you believe the data from the wind tunnel, I believe the P4 is a minute or so faster than the P2. Of course, another guy in my department who's an absolute BEAST of a triathlete (and a hell of a strong cyclist) got a P4--as if he needs any help reducing me to a babbling heap of flesh.