I just bought a GAP tool a few months ago. I've used it to read the faults from the various ECUs. It returns all sorts of faults from engine, electrical, suspension, audio/nav, etc. I'd have to get on the GAP to see exactly but I think there are like 13 ECUs read? It's told me what I already know about my audio issues which is the MOST ring is incomplete and there's a communication error. Not much help there. I had an intermittent check engine light a week ago and it told me there was a MAF error. Cleaned both MAFs and all good now. I also used the GAP tool to set my baseline "normal" suspension height to +26mm front & rear so the truck now considers normal height 1" higher than the previous normal. I did this because of my larger tires occasionally rubbing in the passenger rear wheel well (still have to relocate those rear cooler lines). I have the XLifter module so I can override the OEM suspension controls but sometimes the XLifter zeros out when the truck is restarted. Now with the +26mm setting I'm still 1-inch over normal even if the XLifter is at zero lift. You can also raise or lower the front & rear independently and set it at your desired height. I wish you could do all 4 corners independently. There's a lot more the GAP can do too but I haven't much explored it yet.