Installed along a CS bottom bracket. I can't measure watts compared to original spec pulleys but it apparently made gear changes snappier and a little faster; this in the overall run should translate in fewer or shorter "dead spots" and thus reduce your times.
It looks really cool, elegant, almost as if it came with the bike (compared to previous OSPW version). I got the alpha version which is supposed to carry a lifetime warranty as bearings are protected from contamination.
