I've had it about a week now, so here's some observations:
I've tried the top two performance levels so far. I can't really tell any difference in performance based on boost, EGT, or seat of the pants. I really have to watch the go pedal before boost is built up on both settings, because I can really make it smoke (big-time). I don't remember the EZ smoking anything like this.
Also, now that I've had some more chances to really step on it, I'm concerned about how much my EGTs have gone up for only a few pounds of boost gain. I'd say they are up 100-150 degrees overall. 1200 degrees comes up pretty quickly and I can hit 1300 on a long run. This seems high to me considering I have a BHAF, and 4 inch exhaust and boost module.
When I really hammer it, boost will spike up to 35 psi for a second then settle right back to 33 psi, almost like its correcting itself from being too high, although I have a boost module.
I just made my weekly 220 mile trip from Seattle and got 20. 7 mpg, just over 1 mpg better than usual.
Overall, the price to performance seemed attractive at first and I like the speed correction feature. The honeymoon started to end when I noticed the EGTs and smoke. I won't be able to tow anything. The instructions recommend it for unmodified trucks only. Just thought you guys should know what I've experienced so far.