For these special hybrid kits, only the Race Pro is offered. It's the perfect muffler for high HP applications as it flows the best yet is also the quietest. If you have a motor that warrants this system, I doubt you want to be any louder than what you will hear from these mufflers. The Race Pro is literally identical to the Magnaflow, DynoMax ultra flow and Xlerator mufflers. Same design.
