i work in auto salvage, i've seen some changeovers go for that, but its a little high, imo. the mileage has a little to do with it, and the complete harness as well, but the ecm doesn't really sell for alot. trust factor is hard to measure, though. do they back their parts with a warranty? we give 90 days on ours. i wish i had one with decent miles, i'd hook you up. you could try carpart.com if you want to check into some prices. if you can find one thats still in the vehicle, the yard should be willing to let you hear it run before they pull it. if they aren't or can't then i would question that. even if i don't get a key with a vehicle, i get one cut so i can run it before pulling to make sure its good. also, if you do hear it run dont just run it a few seconds and then cut it off, get it to operating temp, that is when the funny noises tend to start. rollovers tend to smoke at first as well, but clear up after the oil burns off the top of the pistons, so not a big deal. look at the condition of the vehicle as well, even though its wrecked, you can usually tell if it was well taken care of or if it was beat like a red headed step child. hope this helps.