Manifold height?

I think I would have to agree here. If you're not going to Drag the car, just like we talked about in your other thread, I just don't think you will get the use out of an Air Gap. For most street applications anything from idle to 6500 is plenty and if I remember right the Performer RPM is advertised in that range. Same with Weiand's Stealth Intake. Lots of brand options out there and most of them are going to perform about the same. Some may be a little smoother as far as the ports are concerned which will help flow, but most likely not enough to be noticeable unless you are trying to pinpoint ETs for the drag strip.