MP2 powerful but needs to be run at high rpm, 2000 on the Raptor, a bit loud as well.

Hatori SB50, smoother at different rpm ranges and the same power as the MP2 and its quieter, its also pricey.

Either one are great but a stock muffler is fine unless you are looking for that last bit of power and want to run a metal head, 2000 rpm head speed and 30 percent fuel.