I love my 07 gsxr 1000 tons of power with a few bolt on's as far as extensions no more than it's extended it wont change handling that much but try keeping the 07-08s down 1,2,3 gear with out extensions with a few bolt on's nice bike free bump
the ext swing arm will def help with tire lift if you dont want that, but if you ride mtns constantly like we do in my area, it hurts handling a considerable amount.