You are not buying a new car, you are considering a ridiculously expensive, awesome machine. The original price of a this beast was...wait for it...$169,000. And you are going to pay what, $50,000? The original owner paid $22,000 a year in depreciation alone. Are you willing to pay 25% of that in repairs (per year) to drive a car that is not exactly "new". As long as you have realistic expectations and a thorough inspection I say, if you can afford it and you value a marque like this S65, then go for it.
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