Does anyone know (or have you tried to fit) the "aftermarket" GYT-R Header Pipe into the stock 04WR450F muffler. I have destroyed my header pipe biffing on rocks and must replace it. The price for the GYT-R header is actually cheaper than the stock pipe and I would like to use it for better price and more power. Unfortunately no one can tell me if it will fit my stock muffler. I believe the Yamaha website quotes it as having a large diameter stainless pipe for better flow, power, etc. Question 2: Are there any other aftermarket header pipes for the 450 that would fit into my stock muffler? For example would a FMF , White Bros or Yoshi header fit into this muffler?