i have a white bros e series on my warrior and love it. its the only pipe i've ever seen that actually made the head pipe cooler. i've had several other pipes and the head pipe was always putting out alot of heat but with the e series it isn't much hotter on the exaust side of the motor than the other side. i'm not sure if that really makes a difference but a cobra pipe won't run that cool even if it's jetted rich and the baffle is out. i cant really say to much about performance because i added other stuff at the same time as the pipe. i have been happy with it though.