I have a white brother e series exhaust on my yfz450, alot of my friends i race with run different pipes but they all have theres cut down to 7 inches or so......i have seen alot of pro riders have this done to. I was wondering if it was a good idea to do it? It is like 15 inches long now i was thinking of taking it done to 7 1/2 inches. My buddy owns a machine shop and is going to do it. He did his and his brothers and they look awesome but, they have a yosihmira and a hmf.