jet pro knock offs fit but you have to cut the cross bar under the seat....jetpro vs fatty... jetpro is a low to mid pipe while fatty is mid to top pipe...both are good but the fatty has been known to crack....
just remove the bar and use a jetpro rep.. you can have the bar welded back in.. a little higher up(under the seat) if you're worried ...
the difference in the pipes really comes down to how you've set up your motor... but for a basic setup, you can't beat a jetpro rep....