Wow. So this saga is getting closer to an end I believe. I had him come over today so that we could try securing the connectors to make certain it wasn't his soldering that was contributing.
We hooked everything up, and I first tied down the battery connector to the chassis. I put out one of the ramps so we could run it over that to see what the effect was. He plugged in his battery, turned everything on, and started to run it out of the garage. He didn't get but 10 feet before smoke started rolling from under the body! The culprit - the capacitor blew.
So, he now has a burnt pile of crap to send back for retesting. I'm going to type up a synopsis of what we've tried, and he can attach that to the form, including the above picture.
After this occured, I put one of my old 4.5 systems in it, and it ran great. No cogging/glitching at all - even after landing a jump so hard that it snapped both rear shock mounts off the bulkheads! Yeah, he had a rough day!
Kinda sucks that this thing was returned once already - with a "nothing wrong" response.