Hi all, I am new here. I did a search but could not find the answer I needed. I bought a used 2001 426 with a White Brother pipe. It is too loud for my taste. It actually regisered at 106db. It has the free mods done. My question is this: Which stock pipes will fit? Can I use a 400, 450, YZ? Will I notice a big difference in power once I switch back to stock? Thanks in advance.