As a Porsche and Z owner, I can agree with your statement about the high cost of Porsche repairs. It's interesting that the 911 link you posted states the car has a bit over 60,000 miles. Could be the owner checked the cost of the 60K service and decided to get rid of the car. Not uncommon. Operating cost per mile on the Z is significantly lower than the Porsche. For the budget you mentioned, you should be able to find a good west coast Z and ship it East, if a Z is what you really want.
dennis