Matt...I have a hemi, but I switched to a larger cast manifold (Indy 426-4). Has more plenum and runner volume than the Ray Barton manifold I had been running. Both single dominator manifolds.
The bigger manifold was stronger up top, but it never made up for what it lost down low. 60 foot slowed 1/2 a tenth! I never expected my 572" motor to be affected like that.

With the nitrous it might not be a big issue, but on motor you MIGHT be disappointed. It may run great, it just seems like a similar scenario to what I was in w/ mine is all.
It would have been better in my car if I had the converter loosened up a lot and was able to turn more rpm, but that's not at all what I wanted to do w/ it.