Well top update, I passed on the '92 500SEL and have since found a local '93 400SEL. The good news on this one is that the engine wiring harness AND the A/C evaporator have both been replaced (by Mercedes tech) and it has service records to prove it. Its in excellent condition, garage kept, service records (serviced at a local Mercedes shop) and in perfect running order. Its not cheap, but I think it will be better in the long run. Going to check it out this week.