Our custom headers have been tested on some of the most powerful porsches to date turning incredible 1100 rear wheel HP. 304 stainless steel 1.75″ primary tubing coupled with our custom 3 into 1 merge collector is hand crafted, TIG welded, ported inside and polished to mirror finish. Our cnced custom header flanges have .25″ step down on the inside that allows us to drop in the primary tubing and weld inside and out. This prevents warping and cracking from excessive heat meawhile keeing the inner diameter of the flange matched up against the head for maximum flow. The header comes with a dump tube using tial 44mm wastegate. We offer these for the GT30r, GT35R using popular Tial V band exhaust housings. sold as pair.