Well I can CERTAINLY say that replacing my pulley bridle lines on my SB2 made it fly like a freakin' new kite.
On this subject... to reduce wear on the pulley bridle lines, I started this thread about replacing the cheapo plastic pulleys with stainless:
http://www.fksa.org/showthread.php?t=6323
Anyone have any thoughts on this subject? I want to REDUCE the wear on the bridles.