Originally Posted by hamster

Drafting makes a huge difference. Here's a crit track of a guy who averaged 191 W and 25.5 mph for half an hour, and placed 26/53 in the category 4/5: http://app.strava.com/activities/6441896# This guy averaged 180 W and 26.8 mph: http://app.strava.com/activities/37546363# 191 W gets you somewhere around 20..21 mph in the drops without drafting.

3:30 metric century is an okay time, I think, if it's flat. If 20 minute distance can be improved from 6.5 to 7 miles, that should put the OP in the right ballpark for cat 4/5 races.