Unless you're planning on regularly running north of 3,000 RPM, I wouldn't bother with the Hughes AirGap. Yes, the kegger is restrictive as hell and yes, you aren't going to kick out tons of power with it but what you will have is plenty of low-end torque which you really need with a heavy, automatic truck.
But what it really comes down to is what you want and how much you want to spend. I've looked to nab an AirGap or M1 for quite some time but ultimately decided that I'd rather stick to a low-end grunt setup than anything hot-rodish. I mean, my truck as it is isn't going to win any drag races, but I'm happy with my 0-70 acceleration as is and I'm not finished with my bolt-on stuff yet (still wanna get HS 1.7s and some ceramic-coated shorties) and the engnie will happily hum 2,300 RPM at 80 MPH with a single-exhaust setup. Hell, I could cruise 90 if I wanted but my front-end is a little loose for those speeds plus I don't always spot the brown hats right away when I'm busy jamming to Metallica, LOL.
Bottom line is with a tune and some bolt-ons, the kegger isn't nearly as bad as it's reputation suggests. It's no hot-rod manifold but it gets you going quickly and will still breathe good enough for spirited cruising. Spend a few bucks and ditch the ****** factory gasket with an updated one or get the replacement aluminum pan and you're good to go.
Also, for what it's worth, your acceleration will drop significantly after 3,000 RPM with the kegger. Me, I seldom accelerate that hard not because I don't want to but because I respect the limitations of the kegger and am happy with my torque under that RPM anyway. I've got enough power with my tune within that small range to where I can handily stay ahead of approaching cars when I'm turning onto the highway. And if I REALLY want to be serious, I can auto-stick the transmission which is especially effective ever since I got my tune. I don't do it very often but it sure is a nice option whenever the case may be...