I'm certainly no engineer/performance builder, but i wonder if you could do log manifolds in an N/A format? You may loose a little power, but it would get it on the road(providing they fit)
I think something like that would probably fit, but as you mentioned performance is an issue. I don't know how to weld, and something like that (as simple as it kinda seems) would probably not be worth the money to hp cost. I may be wrong, never actually seen that type of header on a NA application.
