Doesn't seem like a bad car, IMHO still overpriced. It does seem to be in really nice shape though, and they are right about the car's advantages. They seem to be enthusiasts, and those are the best people to buy cars from. They've listed quite a few of the required service items, which is excellent.
OTOH they're quoting dealer prices. A timing belt & water pump is roughly $200 and an afternoon.
ECS Tuning sells a full kit for $160, I'll bet you could assemble the parts even cheaper than that.
I'm just sniping, I know, but if they fix up BMWs, why would it need a windshield? If it was recent damage, I'd understand, but a new one can be less that $200. That can be a ticklish job to install, but the E30 is just a rubber seal with a locking strip, not an adhesive bond.
Given, the market for E30s is heating up a bit, but I still think it's too expensive. For that kind of money, I'd be sure the A/C and heater both work perfectly, and that a desirable ratio LSD is installed and functional. A 3.73 medium case diff should be stock for that car.