I just installed a white brothers E2 on my 2005 XR650L, I am running the Dynojet kit with a 160 main installed, needle e-clip in 3rd position, airbox snorkle removed and UNi air filetr, IMS smog block off kit. Started it yesterday after installation of the E2 pipe and loved the sound, performance is ... WOW! motor seems to be using less effort overall, 2nd gear roll on wheelies at just a twist of the grip. The only thing I encountered in installing the white brothers E2 was that the aft fender mount hole had to be drilled to accomodate the spacer (spacer bolt diameter is larger than the OEM 10mm hole). Now I would like to move onto I think some acerbis handgaurds and also some smaller - yet functional dual sport mirrors to replace the stock ones, that seem to be so tall! I also have an XR400 front fender on the way. Other mods done to bike, Baja designs skid plate, acerbis fork and disc gaurds. I love my XR650L!!!! wonder why the OEM guys plug em up so bad! they run sooooooooooooooooo MUCH better uncorked! I know EPA is part of it, think they would go after bigger polluters than bikes!