I've had my car (1990 964 C4) for over 6 years, It's be a great car with killer performance for it's year and awesome MPG, around 30 at 75mph. There great cars with lots of parts to upgrade. I purchased it from a Porsche dealer (smart when ever possible). They had all the records (1 owner) and the car had been serviced by them the entire time, previous owner drove it instead of a lot of 911 owners who just rub it with a diaper, my car had some milage on it. Not high for the year, about 90K. I've had lots of 911's over the years & I think (964's) are the most fun for the $. Buy a car that has great records, miles aren't that big of an issue, especially if your going to enjoy it as I do!
AWD, Performance, low cost of ownership, easy to work on & to do it's services, Great MPG, low cost of insurance for good drivers, drives on rails!!!
Heat and A/C can and will most likely need to be serviced from time to time, but not that hard or expensive.
Spending a little on suspension, coil overs is way worth it, along with exhaust.