If you feel like re-gasketing the LIM, blower and valve covers, installing new coolant elbows, coolant flush/fill, new plugs and wires, 1 replacement wheel and possibly a hub assembly (could be the reason the ABS light is on) and installing the factory pulley back on the blower then go for it. And no, likely the head gaskets are perfectly fine. That screams LIM gaskets to me. And they obviously did not care for the cooling system in their "maintenance upkeep". The brown sludge is a dead giveaway.
The performance PCM would also get pulled out and replaced with stock if it were me. No telling what "canned" tune is on that thing. Could be KR city and waiting for "Chip" to stop by and say hi and then it's bye bye motor.
Personally, I'd hold off on it and find one that hasn't been modified but just maintained if you really want another GTP. Assuming you can do all this work yourself it would still take some cash and time to make it right, which with your 3 kids, a wife and the holidays coming up I don't know how that would work for you. Sounds like a stress inducing project to me, lol. And who needs that especially around this time of year? That's what in-laws are for
