I finally decided to give the 1991 525i a review. I only drive BMWs and the 525i is my 3rd beamer (automatic), I prefer manuals but... My 525i has 243,878 miles on it and it still rides smooth, tight and stiff. I did put a transmission in it at around 210k because the 3rd gear went out. Above all the regular maintenance and small things that goes wrong, like the cig, lighter(s) not working, I love this machine. It's the bomb.
Road handling A+. Rear windows go all the way down (unlike American made cars). Front grill, the width of the car, trunk space, radio, tool kit, center console (I use the intergrated phone area as a cup holder) works great! Door locks, roll up the windows with the key, all sorts of good features.
Car mats, cigarette lighter unit, dual climate control for front and back stopped working early on, windshield wipers should be better quality. Rear lining by rear speakers should be replaced with the same lining used overhead.