Ive got a 06 600H.O. and finally the carb boots needed replaced this year, as far as that goes I havent had to do any of the other Fusion upgrades... I have nothing but good things to say about mine...SLP Pipe, SLP Can and SLP air intake and no I didnt gut the air box and I still run 420 mains..... 102mph on a good hard pack.... bottom line from me is, if it isnt broke dont fix it. Best of luck to you, I have zero complaints.