anyone using gn1performance headers? or tta perf? im just fixing to buy a set and was just wondering gn1 has em 304 stainless, for $ 600 they look like an old set of kenne bell headers, and they have the stock appering ones 304stainless for $ 550 looks like a pretty good deal to me, tta wants like 800 to 1000 for theres, anyone using eather?