my best friend and riding buddy has a 07 450r just exactly like this one, but only has a pipe filter and jet kit. we clocked it on the road at 75mph and it wasnt topped. i cant imagine why you would need more power than it has already unless you were a pro. it is stoooopid fast. will pull wheelies in dirt in 4th at 50mph. it makes me wanna change sides!! damn honda!