Hello - I've been reading through past posts on the subject but I'm looking for a clear answer on this. I'm about to take my aveo into the shop for a custom mandrel bent tube exhaust. The mechanic said doing a custom header would take some time and he started to whine about it, but he seemed more enthusiastic about me buying a header for another car since none are available for the aveo, and just modifying it to fit.

I've read on previous posts that the civic D16 performance header on ebay is a good starting point, and can be modified to fit. Is it difficult to modify? What needs to be done? Does this leave enough room for a magnaflow high flo cat?