RRR you are correct. I agonized over headers vs manifolds my research showed that even on a mild plus street engine the difference was 20/30 hp
I know that many will disagree with me but you won’t really feel 20-30 hp in the seat of your pants. Also consider heat production, fitting problems, burnt wires, gaskets, rust, low clearance etc.
Not to mention that a really good set that doesn’t have high frig factor to fit is 400-500 bucks.! Don’t ever think my exhaust manifolds will wear out. I built my car to cruise not work on all the time
I can street race at night and my wife can go to the grocery store in it the
next day, and do it with 500 hp on tap
