This car was owned by my parents before I had it, and I have been living with them so I know what's been fixed and what hasn't.
The air conditioner failed around 190,000 miles and the evaporator had been leaking for some time before that, repair cost was under $500.
The heater core failed at the same time as the evaporator probably due to the excess moisture on it since it is right next to the evaporator. $200 repair.
The belt tensioner for the serpentine-style drive belt failed a number of times before the 100,000 mile mark. It has not failed since the last replacement (winter 1999 about 100,000 miles). The first repair was about $400 and subsequent repairs were covered under warranty.
The original Michelin tires lasted forever so my parents bought another set of Michelin tires and then another, and now the car has cheap tires on it which are much noisier.
The transmission has finally developed some issues and if the car is driven hard it will slip between gears, in normal driving this never occurs. I expect many more miles out of this transmission with the way I drive.
The muffler was replaced at about 160,000 miles not because it failed, but because the outer casing was eaten by rust.
The brakes were a problem in the 100-160,000 mile range because of a stuck caliper. Once the failed caliper was replaced, the front brake pads have only been changed once since then, and have plenty of life left. The rear brakes have only been replaced one time since the car was new.
Many of these 1990's GM products have a cup holder mounted in the armrest that breaks off easily because it is made of thin plastic. It *just* broke. I'm looking for a replacement.