I have a 1979 Garelli Super Sport LTD top tank moped and would like to boost its performance. Right now it runs at around 26mph it used to get 30 at least. I am completely new to this subject and would like some advice if possible. What kind performance exhaust would be compatible with this bike? Or does every new exhaust require special modification? And it has a jet #50 installed.. Would a new jet improve its performance.. and if so what size, and where can I buy it? Thanks for your help!!