What bike? What are you looking for? I.E. Speed, low end, noise? Some pipes give different characteristics. Are you talking full exhaust, just a silencer or just head pipe? Also remember when you change a exhaust it may change your jetting so be prepared for some fine tuning.Ride it back to back with crf150f. You may find you prefer the honda's ergos.if i ever get a pitbike, its gonna be a klx140L again, so underrated, the stock exhaust makes people think its a gutless bike, put a pipe on there and you will be sayin damn