[mirage83]

MkIII Supra's in general are like high-maintenance girlfriends... Be prepared to spend on them and do so often. Seriously, unless by some miracle you get one that's really been taken care of you're going to have regular maintenance expenses to deal with to keep it running. By the sound of what you've got, you're already finding that out.

As far as your '87 goes, you paid $2500 for it how long ago? What's the mileage on it?

You can pick up a decent used diff for not too much, just decide what ratio you want as different years/configurations ran from a 4.31 to a 3.73.

A/C work can get expensive, depends on exactly what's wrong with yours.

You need a distributor? N/A's had distributors, turbo models a cam position sensor (cps). Is that what's bad on yours? New they're obscenely expensive, but bad ones can be rebuilt.

Power steering could be a number of things, hopefully just a low pressure return hose. They aren't expensive to repair.

Your mileage sucks. Could really be any number of problems there, including just your driving style.

Now then, is putting up with all the myriad problems worth it in the end? Depends on how seriously you're into Supra's. For some people they like the car but it isn't THE car. It's probably not worth the hassle to them. If it's YOUR car, then you'll have to decide how much $ you're willing to budget for it every month AFTER you get it running right. Right now I've got approximately $5k in mine, and that's just the necessities for driving (reman engine, various new engine components, tires, etc).

Time for a gut check.