Physically, what's the difference b/t race headers and OFY and emissions legal exhaust components?

 

Race headers do not have the fittings for the AIR and EGR systems. The ORY (off-road y-pipe) does not incorporate the cat(s). An emissions legal exhaust system would incorporate the AIR and EGR fittings into the headers and have a y-pipe that has the cat(s) and still maintain the cat(s) in their stock locations.

 

u can buy the emissions legal headers, and just plug the fittings so that u can later run emissions if u need to, thats what i did.