The biggest advantage is adjustment. Allowing the foot peg to be moved upward for more lean angle.
However, on your busa adjustable rearsets have little advantage since the fat chick is so thick the plastics become the lean angle barrier.
How hard are they to change out?
No, you can lower them.Aww man, I think I had the wrong impressions.. So are you guys saying that rearsets will not make the ride a little more bearable on long trips? I wanted some to give me more leg room and stretch my legs out a little more. I have a 38" inseam so I need all the room I can get.