Post up what pipe diameters and lengths you plan on using. Welding it together shouldn't be too big of a deal for an experienced welder. Designing is a bit tricky though. Diameters, lengths and collector design are all pretty important. I'd be happy to help out. I have a some reference info that will help out. I've designed two headers for other cars I have had. I started making one but never finished it, and the other I never started. Heres a pic of one of them.