I gots a problem and looking for help

[Dwaxman1]

So here's the story,

Yesterday I drove to my friends, about 70KMs from my place, finished installing the overhead and grille lights, with Jay's advice. While we were doing the wiring, i decided to also change the plugs and wires for the new ones I bought, NGK Plugs and Taylor thunder Volts wires, I decided to start on Cylinder 7 as it looked tough at the back and pointed towards the truck, after screwing around with it and not being able to get to it other then from inside the wheel well, I had my buddy help with lots of extensions and a 1/2 ratchet, we tried to loosen the plug, it wasn't going anywhere, so I said screw this, I just changed the wires, finished the wires and I was on my way home, lights all working great and new wires on, plugs I figured i would have the dealer deal with later. Anyways as I was driving home, the truck started to misfire and the check engine light kept flashing, the truck was running like crap.
So when I got home i first checked all the wires, maybe I had not put them on tight, not sure, but they were all good, so i changed them back to factory AC delco ones, that I had took off earlier, still no good, now check engine light on constant.
Getting p1$$ed i called it a night and said I will let dealer figure it out! I took it in to the dealer, Queensway in Toronto, at 7:30am est and now it is 9:00pm est and I still have no truck and they have no Idea. They tried to tell me it was to do with my after market compustar remote starer and how it was installed. They said this but I have had the starter for over a few months now without issue, I am sure it has to do with the plug but they are saying that maybe the starter screwed the ECM because of the way it was wired, I have no clue but that sounds fishy!
So anyways the check engine lights reads as misfire in cylinder 7 and 8, they say they checked the wires and swapped them around but no change, they did a compression test on cylinder 8 and it passed but cylinder seven was too late as they need to lift the truck up to test. They have no tried to flash computer mem or anything else, the mechanic is stuck on this being the starter caused it and saying that it may have screwed the ecm somehow.

Anyone ever hear of this or do you all think that it maybe still be that damn plug we may have tried to get out, maybe we cracked it? Would that impact the cylinder 8 too??