How hot is exhaust gas? Very Hot. So hot, it melted the rear diffuser! But of course, if you set up your exhaust system properly, you would not have such a problem. The Supertrapp end caps directs the hot exhaust gas around the disc compared to the conventional straight through system of normal exhaust system. I had wanted to buy a Supertrapp heat shield to shield the plastic diffuser from the hot air emitting from the end caps but never got round to ordering it. The price I paid is a fairly expensive one but luckily, someone was kind enough to let me have his rear diffuser for the time being. Anyway, I have been thinking about going loud. Those single exit exhaust like Sunline 60SS are really loud and light. The lesser weight on the rear might help to solve the rubbing problem that is really annoying. While the situation has somewhat improved after inserting rubber bump stops on the springs, that is probably not the safest method and certainly, not professional. This problem should be solved once I buy over my friend's Tanabe Sustec Pro.