I replaced the rotors and pads soon after I bought it. I got everything top of the line, so the brakes have never squeaked once. The master cylinder was rebuilt - it leaked - and much of the general brake system replaced with an updated, much improved one.
Nearly all of the steering and suspension bushings had to be replaced. After 20+ years, not surprising.
The tachometer and green "idiot" lights go out, and speedometer sometimes goes out. I just haven't pulled the instrument cluster out and replaced the wiring.
Other things are minor and only slightly annoying or cosmetic.
The rear right side window motor is almost shot.
Slightly cracked dashboard which I am loathe to do myself.
Everything going into this car is better than standard and I would certainly recommend that to anyone considering getting a car of this vintage.
The main reason for the above is: there were no available maintenance records when I bought it. A Car Fax Report came back clean and general inspection of the car was really very good. All the broker felt he needed to do was replace the radiator and belts. The car has never been wrecked.
With regular vigilance and maintenance, it should go another 100,000 miles or more. The engine is absolutely solid and has needed nothing, but regular oil changes and a tune-up. Lots of power and superb handling typical of any well-cared-for BMW. I absolutely adore this car and will gladly put more money into it. It's a daily driver. For the first 6 months I had it, I commuted 80 miles round trip, plus extra miles, some days totaling over 100. It's never acted up or given me any trouble. Now it's just as fun on shorter trips. Quick and fun!
I have owned a 1984 533i since 1997. It has been my one and only daily driver. It had 113K miles. when I bought it - and now has 177K miles. Basically, the car has been re-built. Although very expensive to rebuild it throughout the years, it truly is a very rewarding automobile. The 533i, in my opinion, is extremely rare today - almost more so than a E28 M5. If you can find a nice one, buy it.
The chassis (E28) is very solid, and the motor is the kind that made the company famous - In-line-6, M30, SOHC, 181HP, 195lb. ft. torque. Curb Weight: 3,200 lbs. est. 0-60: man. 7.7, auto. 9.4 sec. The E28 5-series (`82-`88) has an enormous trunk (same size as 750iL). Top Speed: 129-134mph.
Beware of rust. Look at inner door-panels, rear fender well lips, valence panels, license plate lights, gas tank, rocker panels, and that's usually it.
The 533i used the infamous metric TRX Tire/rims package as standard equipment. If the vehicle still has these wheels (15.4"), identified by Michelin TRX tires can only fit size 200/60 or 220/55 - the rim/wheel is 390mm which translates to 15.4". These tires are very hard to find, except for the Tire Rack or Coker Tire. It is common to replace these wheels/tires with more contemporary ones (14"-16"). Although the original 20-spoke, metric/TRX rims do look superb!
If you buy one and want to really take care of it you must do the following: Check the valves every 15K (inspect Banjo-bolt sprayer bar), use a heavy-grade oil (15W-40 or 20W-50), use only BMW Coolant (change every 2 years), Trans. fluid flush every 30K same with Differential. Keep it clean! Wash it, and wax it as much as possible (wax at least 2-3 times a year) - don't skip out on the rear or front lower valence panels - under bumpers. And Condition the leather (at least twice a year). The dashboard will crack like crazy unless you treat it and/or cover it when parked in sun (windshield sun shield may help too).
Overall the 533i is a collector car in my opinion - but can certainly be used as a daily-driver. Only 10,000 533i's were produced from 1983-1984. Bear in mind, the 528e (`82-`88), which looks identical from 50 feet away, was produced in huge numbers (over 100,000) - so comparing this to a 533i, you can see why the 533i is indeed, an endangered species.