I bought my 1997 Supercharged Riviera from the original owner with 37,000 miles on it. I commuted 100 miles round trip to work each day for 13 years. I now have 409,000 miles on it. Parts replaced included 3 water pumps, 2 alternators, a starter, entire brake system (minus master cylinder...thats still original). The CD player went to I had a cheap one installed.
One set of tires (Cooper) I got 105,000 miles out of. Had the front wheel bearing assemblies replaced at 250,000 and just had the drivers front wheel bearing replaced. Still the original exhaust system. It has some annoying oil leaks that I really don't care about. Original paint job is my only complaint. Wore off in a few places.
Durability, my drive 100 miles each day was all highway and I got as high as 34mpg with it, but 30mpg was standard driving 60-65mph.
The paint job from the factory is my only complaint. The trunk lid and rear sides at the very end had the paint flake off down to the factory primed metal. Its a big, safe car that looks pretty good for 409,000 miles. I keep up with all the
regular maintenance. Had the transmission fluid changed twice.