The later the production, the better the car is. Earliest cars were literally handmade with parts that were at best considered pre-production quality. Early cars had the the bulk of the problems with the door mechanisms failing, the ventilation systems dying and the engine fires. As production continued, they actually became fairly high-quality cars -- compared, at least, to other low-production vehicles of the time.
The worst problems tend to come from under-utilization -- so hydraulic seal failure, or being owned by people who abuse them (and this is very common.) People often buy DeLoreans expecting them to be sports cars, and they are not. They are GT cars. People buy them, beat on them, get bored, and dump them.
Paint is not necessarily an immediate indicator of damage. Later production cars sat on dealer floors for long periods of time. It was not uncommon for a new car to be painted red by a dealer. It actually looks pretty good.
Parts are available, but engine parts are much easier to come by than trim parts. Engines were PRV units, which appeared in hundreds of thousands of other vehicles.