Anyone run one of these pipes on the 900? I have one in the garage right now, I don't have a silencer for it. truing to decide if I should get a silencer for it and give it a try or if its just a waste of money. It is ALOT bigger then the stock or maybe I could make it work with my SLP silencer but I am worried about back pressure. I feel like the pipe controls back pressure so i should really matter what silencer you hook it to. But if thats the case then whay do them claim a hp gain out of changing the silencer?