299hp 233tq Mustang dyno with: Stillen CBE, Berk HFC, and Stillen Gen 3 intakes. I realize you just want exhaust dyno numbers here but no one else is posting so here you go. Also this is before any custom tuning, still running stock tune.
For some reason my vid will not embed.. Anyways heres the link.
YouTube - 370z stillen exhaust w/stock cats VS HFC + drive