As for the bike choice, I've done it on both a roadie and my P2K. You could go either way, but I really didn't find that I spent too much time in my aero bars. The only place that would make a difference is out on the Great Highway (assuming the crosswinds aren't too strong), and through GG Park. Otherwise, the road bike is probably at an advantage. BTW, my time for the ride was ~ the same on both.

Also, Cathy's right, PAY ATTENTION TO THE SWIM INSTRUCTIONS, last year a friend of mine (who's a strong swimmer) thought he knew better, and lost about 10 minutes fighting the currents back to the beach for the swim exit. He was exhausted by it, and suffered, timewise for the rest of the day. It cost him a podium spot for his age group...he had placed the year before.