[QUOTE=Brian Ratliff;16189597]Depends on the course and the race. A good wheelset might weight a pound less than a training set, which will matter if it is hilly or if you are accelerating a lot (as in a crit). A good wheelset might be quite a bit more aerodynamic and might save you 5 or 10 watts at 25mph.

Carpediem says 10% - obviously his power is greater than 50-100 watts. So that clearly doesn't match the 5 or 10 watt answer
Homebrew gives the very technical "not very much"

I know if I buy some new wheels one of the first things I'm going to do is another FTP test in very similar conditions to my last test and see how much time I saved & obviously compare watts to quantify in my mind the benefits of the wheels. Has no one else done this who can offer solid, precise data.