Originally Posted by
Commodus
I'd buy the CAAD and some nice wheels. The aero benefits of the frames are minor.
I agree with this. You also need to budget for clipon aerobars (my recommendation) or an integrated TT/tri bar.
The bike isn't going to win or lose you the race. Having a budget for a good skinsuit, aero helmet, power meter and so on is critical. Don't buy the S5 unless you can buy all that stuff on top of it.