My experience is the same as RNajarian. I don't think you can get a pile of scrap for 20K now but when I first got into this circus the rule of thumb was that if you spent 10K or 15K (ha! - remember the good old days?) an SC was a 20K to 25K car to own. I haven't found Porker parts prices generally all that bad. Most are quite reasonable and others stupid but I've probably put a few thousand into the car in parts and done all the maintenance myself. Finding and stockpiling parts is part of the fun. Mine needs probably 2K more to refresh the suspension to make it really top tier if I did all the repairs myself.
My SC has definitely been cheaper to own and more reliable than my last modern BMW for sure. It's a solid car.
The PPI is key and you have to buy the best car you can stretch to. If the motor is solid (watch out for head stud issues - big $$$ - recent refresh is good), gearbox good (915 synchros), and you have no significant rust issues then the rest is deferred maintenance and misc repair costs (budget 5K). Check for wiring issues. Most of my repairs were electrical. Significant savings can be achieved by diving in and doing it yourself. Buying tools is fun too
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