Okay, this may be a stupid question and someone may have asked this before BUT, i needed to find out what is the difference between a GSR header and a LS header? I have bolted my B16a Header to a LS head and it bolted right up. But is there any difference between a LS and GSR exhaust. I am asking since I am trying to purchase a header from eBay and wants to make sure what I order is the right one or at least fits my GSR block. BTW its a '99 USDM block. Mahalo for helping!!