The problem is, if I made a nice set of custom headers to fit MY car, it wouldn't necessarily fit YOUR car. The headers have to run through an area where 1/4" clearances are generous, on cars that have factory body tolerances of a 1/4" (or more in some places).
Doug's and TTI's both fit some of these cars without modification. There's no way to make a header that will fit ALL of these cars without modification, the production tolerances are just too big.
Exactly. As soon as you start mixing factory with aftermarket you're going to start needing to make modifications. The more you mix factory and aftermarket, and different brands of aftermarket components, the more modifications you're going to have to make to get it all to work together.
Kinda like how it's unrealistic to say they'll all be as hard as yours.
Uh, the quality control on those Doug's is way better than the tolerances on these cars.