I don't think I've added many mods since I added the Manifolds ..... well, headers. A few retunes. I'm around 350 hp at 6000 rpm on a Mustang dyno at sea level with temperatures in the 90's. At 6400 I'm at 370 hp. The manifolds leaned me out from 11.8 AFR to 13 AFR. You'll need an adjustment to your tune.

Les