RE: OS Performance Upgrades?
Matt52X, on the .91 Surpass, according to Harry Lagman here at RCU, a significant gain can be had with an aftermarket exhaust system. I brazed an extension on a friends header pipe and noticed when the bend was made at the factory, the pipe was partially collapsed. Also the tubing is unusually thick. Performance Specialties is one of the vendors of aftermarket exhaust systems.