There was an article a few years ago in a European Cycling Mag about this, and how a lot of the spaniards were on a kick to have compact frames and LIGHT(!) seat and seatposts (I believe at the time there was a surge for AX Lightness products).

I've even heard this as a valid reason for sprinters to use a lighter saddle.

Myself, I would say yeah, if you are not a pro, then comfort really should come first, especially for climbers, as you are not throwing the bike back and forth so fast, nor does it matter. If you would LIKE to lighten things for this reason, it is completely your perogative.

I may be inclined to say that for a CAT 4 trying to move up or CAT 3 and above trying to get every inch out of his sprint, it may be important, especially when you have not done it and you lose by a wheel.

In sprinting the cadence is much higher, and the saddle (for example) is swinging back and forth very quickly, and very often. If you take a 135gm saddle vs a 260 gm saddle and they have 80-100 oscillations covering 16 inches total (8 inches off center, c'mon I'm just guesstimating..) during a period of 45 seconds of intense effort, I would think that haveing to move the 130 extra grams at the top of the mast all the way to the left, stop it's motion, and swing all the way to the right, repeat, repeat, for every pedal stroke cast in anger, could measure to a few watts over the course of the last 250 meters.

What are some thoughts on this? Again, my view is it is minimal, but existant, and could be a half a wheel length. Any Mathmaticians?