I just recently got a Two Brothers slip on for my F4 and the folks there don't suggest re jetting. Although I have felt a significant boost of power with just the slip on, I know jetting can't hurt.......CAN IT???? I just need to know which kit is best. Can anyone shed some light on this? I also just ordered K&N air filter. Just want old girl to run right. Help me make the right decision. Not to mention, some guy with a 2000GSXR 600 claims he will whip my ass if I don't jet my bike and even then He will still spank me. I want him bad.