I and a partner have an offer in on a 1959 Comanche 180. We are buying it to fly ourselves and to lease back to a local flight club. A fellow pilot and Cherokee owner has told us he thinks the purchase would be a mistake - that because of the aircraft's age were going to end up spending a lot more money than we would expect. His Cherokee has been on leaseback to the club for about three years and says he's spent much more than he paid for it on maintenance. The Comanche were looking at appears to be in excellent shape and is undergoing an in-depth annual at the moment. The aircraft flies regularly. We have an experienced Comanche mechanic to go perform a pre-buy inspection. The engine is at 850 hours SMOH and the prop is at 200 SMOH. We've budgeted $25 per hour for maintenance, 21,500 for a turn-key overhaul with Corona engines in California, an additional $5000 in case a top overhaul is needed, and $4000 for a prop overhaul. Hourly reserves are based upon remaining hours and top overhaul is based upon a projected need in 750 hours. Total hourly reserves, not including maintenance is $29 per hour. The aircraft will not be used for primary training. I know it's difficult to predict what will happen in the future but any experience-based guidance or thoughts would be appreciated.