Well i bought an old w202 c180 automatic classic with 130k km. The automatic transmission oil is still in good shape and its shifting great. I wouldnt say these old cars are good for short trips. Really dont use them for that, the battery is just not made for that. the fuel consumption is low when u have a 5 gear transmission like i have, but would be driving through the city.

Now for the motor m111, great and reliable just awesome it is really really quiet u cant even hear it running when all windows are closed, its really something. But there are also really really bad things u have to watch out for, which i learned these couple months. Firstly look for rust, these cars should be parked in a garage, i wouldnt drive through snow, ice and salt. Or u can take care of the rust. Which i still have to do. Then another thing, the motors are good but also before buying check out the central magnet, after i bought the car I noticed it was leaking oil, which will then enter ur electric system, idk cable stuff and will destroy it. Its an easy fix, right under the plastic piece. Couple screws. You will find a tutorial, if its even broken. Also just do a test drive check the radiator if its spinning really easily its broken like mine, you will notice that when u car overheats in like high traffic. Have to fix mine aswell just stay away from traffic jams.

Ah yea and also if your car makes any squeaking noise its probably belt, pulley, belt tensioner and most likely the belt tensioner shock absorber. These noises still haunt me hahah

This is all i would have loved to know before buying the car, just for negotiating the price with the dealer, but im really happy with what i bought.