I've been modding my cars for a long time and have been to a lot of shops, and for those that has been around would know how JDM companies always get sour eventually. I have purchased and owned a J's racing exhaust for my s2000, my other friend has owned multiple j's racing exhaust for the s2000. To be honest i think the J's racing exhaust (Authentic) is crap, why? because people who owns them especially s2k owners. They would start to rattle due to poorly built resonator if you drive it a bit intensely, the 02 Bung has fell off from other S2K guys in the states and J's racing didn't want to replace it, so AJ helped by pocketing their own money to satisfy the customer. If you search on S2Ki a lot of J's exhaust just poorly made, and they are 100% Authentic. JDM shit is all overrated, but to be Honest again though, their quality and consistency isn't anything to brag about anyway.
Not trying to help J's or AJ Racing but i personally dealt with AJ-R they know the pro's and con's. I had great experience dealing with A&J Racing
http://www.s2ki.com/forums/index.php...=718060&st=100 This was posted back in Dec