I purchased my Monte Carlo from my uncle who bought it new. It had a few minor oil leaks and some transmission leaks. It was easily fixed and now it currently has over 225,000 miles. Not one spot of rust, though some stone pecks. The doors haven't dropped at all. It is just as quiet as ever. This one has the 3100 engine. No problems yet. Though the gas mileage isn't as good. I average 24-27 mostly highway.
It still goes. No hesitation after 225000 miles. Plenty of acceleration. It feels like it leans into the wind. Plenty of go power when you need it.
The doors are way too long. If you park next to another car you have to contort your body to get out of the car. Trunk space could be improved. Also this car in not pretty.