I read in the 90s when the TTIs came out (had a different name I cant recall! CPPA?) that they were "inspired" by the thick high quality Doug Thorley headers. Both brands are made from real steel-thick steel and not tin made for gutters. But it will cost you alot more to buy them raw- then get them ceramic coated inside and out at a later date. The shipping to and from a coater alone will floor you. I bought raw Thorley headers for my 360 Demon. Bought them that way JUST in case I have to ding them for clearance.But after pricing coating and seeing the high cost I will just paint them myself after verification they fit and engine has been sorted with a different set of cheap headers. Actually Ill probable try the Eastwood ceramic coating DIYer kit.