1980's BMW 3 series questions?

[HelloDarling]

Im shopping around for one preferably a 4 cylinder. Just wanting to know if these things are relatively reliable and get good gas mileage since ill be driving about 300-400 miles a week. I know parts are expensive but I do all my own work and can fix about anything so that isn't an issue along as I don't have to do it often.

 

[thebax2006]

Just be sure to check for the rear shock upper mounts being rusted out. If the back of the car is sagging don't buy it!