I had Gnarly on my CR500 and the thing was like a John Deere, atleast I thought so until I got the KX500 with VForce Delta II, Reed Spacer, flywheel weight, and FMF Fatty. This thing could tow a house and at any rpm range
I think Destry races all his stuff with the Gnarly on his 500. I know the Gnarly is a more bottom / lower mid pipe and the fatty is a more overall pipe. My next pipe is going to be the Gnarly.