I purchased a full Yoshimura exhaust system. After a couple of months I noticed the pipe turning gold, then after a while it turned bluish gold at the bend in the header; I called Yoshimura R&D. they said it was indeed stainless. So I purchase some "Autosol". With minimal elbow greased the pipe look brand new again. I know their are other brands but this one worked for me. One other thing this thing tends to pull the front end up high enough to hit the rear fender. This thing is very torquey with just the Yoshi system and a K&H high flow filter. It will pull the front wheel in second gear also. I'd love to race a 2015 Ninja. I'm in talks with Bazaaz about developing their Z-FI for the cb/cbr300r/f... Lets hope so, since Dynojet doesn't seem to be interested.