ThumperSRT-6 and I both have the big manifolds, but mine aren't on the car yet. He lost a bunch of power after installing them and getting a dyno tune. We both run 12.1@114 with different setups. We are both currently running can tunes from EC (different ones) and he's finally getting it dialed back in to pre-dyno tune times. Take into account that these were hand built motors so they don't all perform the same.

Mark, you seriously need to stop trying to mod this car like it's a freaking Mustang. If you think merely adjusting your fuel pressure will get you everything you think you need, go for it. I'll wait here patiently for the post about your motor blowing up. And if you want to compare power, I'm in Naples all weekend at the Ritz-Carlton Golf Club.