So, I posted this in the trackdays section for a reason. I don't care about sound or appearance. I am looking to upgrade to a full exhaust. Either the Akrapovic race series or one of the Yoshimura Rs-5 full exhausts. Do you guys think there is really much of a difference performance wise between the two? And then secondly, as far as Yoshimura goes, do you guys think there is much of a weight difference between the full stainless, partial titanium, and partial carbon fiber system? Trying not to waste my money on names and labels and only spend extra if it makes a tangible difference...