I was wanting to fab mine up from Inconel...lots of Nascar shops near me but all their tube is huge....1.875"+. Hoping to find some smaller tubes for a 2 into 1 step header design. Seems more likely for me to fab them from stainless as it is much easier to locate mandrel bends. A 4 into 1 collector would help scavenge exhaust pulses and kill some Db's a bit. I have been searching for mandrel bent .032" stainless....waiting on a couple samples now after looking into some race bike shops for tubing size I want.