I just got the 19's built with powertap pro+ to replace stock bontrager select wheels on my Trek.Even with the powertap my bike is one pound lighter with new wheels.I didn't buy the PT head unit(I have a Garmin 705) wheels with powertap$1200.00.It would of cost me $1100.00 for the Ksyrium SL's without a powertap(I was going to buy the ksyrium's but stumbled upon williams web site when looking at some climbs in this years TOC.