I have an 06 GSXR 600 and i got the lowering links. The bike handles better! and is easier to throw around because of the slightly lower CoG. They are offered from many companies as upgrades BECAUSE they change the geometry. Lowering the rear of the bike changes the head tube angle of the front forks, which some say improves handling into and out of corners.
If you need to lower the bike solely because you can't solidly reach the floor, shave the seat. if you are tall enough, but just want your bike to look more bad-ass and handle more precisely, lower using links.
As for seat shaving..... take your seat off and take it to any upholstry shop. ( ifyou take it to a bike shop, you risk getting over charged), as they just un-staple the seat cover, take a spinning disc sander and sand the foam down and re-staple the seat cover back on.
http://www.nycparts.com/index.asp?Pa...ROD&ProdID=282
Either way, the solution is cheap.