Get the 928, you won't regret it. In the few years that I had mine, I spent ~$200 on repairs. Maintain it well, and it should go for a long time.
If I had it to do again, I'd get another Euro-spec (grey-market) 16V 928 S, or a 928 GTS. The US-spec 16V was shit, and the early 32V S and S4 were nothing to write home about. The '89-90 928 GT got a boost in power to Euro-928S levels, but they were rare and still command a premium. The 928 GTS was the last of line, and can be had for ~$30k, whereas a Euro S will run you about nine grand -if you can track one down. Look for a rear-fog light and adjustable headlight height knob to the left o the drivers seat to ensure that you're getting a genuine Euro-spec car.
