I've heard the alternator can be problematic- I dunno, bought my car with 53K on it, closing in on 100K, I've had basically zero issues with the car. I did have to replace the ball joints at 70K- evidently this is not uncommon. Otherwise it's been solid. I drive it daily from about April-November (actually just tucked it away for the winter tonight). It's a fun car and the 3V is still relatively simple to work on if you do need to do work on it.
I did the plugs at 80K, all came out in one piece except one that the hex spun off of and I had to get the Lisle tool to remove it. Fortunately if one does break the Lisle tool makes it relatively easy to get out, but it's an annoying job, you have to let the plugs sit and soak and work them out a couple turns at a time.
Also, if you get a GT, get a oil catch can on it ASAP, and you might as well pull the throttle body off and clean it. When I first got mine it was idling low and throwing a code, turned out it was because the throttle blade was all gunked up with crap from the PCV.