Originally Posted by Dave Mayer

Nope - weight trumps everything. When riding in a pack, the weight penalty of a heavy bike, and especially heavy wheels will shed you off the back. Then you can be aero as a bullet, but you are not going to be able to reconnect.

When you are sheltered in the pack, your super aero bike might save you a handful of watts, but then you're coasting along at 25 mph expending what? 100 watts total? Joking with your pals about the movie you saw last night and eating a energy bar...