My dad has a '69 Mercedes Benz 280 SL. It runs and drives reasonably well, but has never been restored. Good body, no visible rust issues. OK older paint job (older = 25 years), seat covers, carpet and fabric top replaced 10 years ago. Engine run well, but smokes (needs rings/rebuild), transmission and clutch are good. Diff. is noisy, steering and suspension needs going through. Fuel system from tank to injectors good, shocks and tires are good. Heat/vent system in-op - levers broken/cables frozen. Dad has been talking about selling it and by chance I had it out the other day and a serious buyer offered me $17,500 for it. The buyer is coming tomorrow w/ cash. I can still back out - AM I MAKING A HUGE MISTAKE?