MJS headers are OEM with a cat delete, also powder coated. Gen one are true 06-09 Headers and will fit with race plastics. Gen two are R6S headers modded to fit with a cat delete, powdercoated as well, BUT do NOT fit race plastics. They say with a BMC filter, good oil and their full kit it can put down 7.1hp on the dyno. I doubt it but thats the response I got from MJS. They both put down the same HP numbers but only the Gen one will fit race plastics, so if you have no intention of racing your bike then this may be a cheap option for you to delete your cat. Remember these are not tuned headers, just OEM modded ones. Also graves full system map with the gen 2 and the akra full system map with the gen 1 if you are going to run a PC.
Hope this helps....