I already have the best out there on order: Carpenter Racing Megaphone 3 into 1's. More net hp gains than any mentioned above. Far superior
Carpenter Race Engines
I beg to differ.
I changed many things during its evolution, but I got the exhaust right early on.
I haven't seen back to back comparisons with Carpenter's, but I gained 27bhp over ToRs and CAT delete. Same dyno, same tuner, same day. Burbles threateningly through town and howls like a banshee when hammered.
Long headers and short Supertrapp means it's easy to shove a probe up to fine tune individual pots.