Just installed a new yoshimura pipe on my 2012 RSS. sounds great. :2thumbs: I used the original y pipe gasket but planning on replacing it. There is a lot of talk about the O2 modifier from evolution that richens up the mixture some to end the back firing. My :ani29: backfires only once in a while with the yoshi pipe but I really wish it didn't at all. It there another O2 modifier supplier since elvolution is not around anymore??? Any feed back would be most appreciated
