I once had a 1987 Mazda RX-7 that I paid only $700 for. It ran, drove, turned, and stopped, but it did absolutely none of them well. I loved the Wankel rotary engine in that car, and despite a completely worn out suspension, the car felt so perfectly balanced right in the middle of a drift.
The wiring in the car had clearly been tampered with over the years. Being the inexperienced and optimistic guy that I was at the time, I decided to rip all of the factory wiring out with the intention of reworking the entire car. Needless to say, that project never happened, but I did end up learning a lot.