I recently swapped out the stock Ksyrium SLs on my Scott Addict R1 for a set of carbon Reynolds Race 32 clinchers with Schwalbe Ultremo tires. The change dropped about 0.7 lbs from the bike, for starters -- a pretty substantial weight change. My bike with pedals and cages is now 14.1 lbs.

My first impression was that the road felt smoother, and the bike felt more nimble. My speed increased enough on level roads that I now am riding 1 cog higher. I haven't noticed any crosswind issues, but then it's not very windy around here.