I have installed the MSX Sport head pipe and run the stock can. Noise wise I notice no difference compared to stock. Power wise hard to say. When I ride with my other grom buddies that have exhausts they dont pull away from me. Some think mine has better bottom end power. The way I see it is with a reset ECU I get a few more MPH until it remaps itself and thats with a stock exhaust. So the big restriction isnt the exhaust its the ECU. But the head pipe doesnt hurt, I think it gets up to speed faster, top speed is maybe a little better. Again ecu gets in the way. I wish I could get a better looking quiet exhaust but I havent found one. I like the idea of the CBR125 exhaust on the grom, low mount and quiet.