I would have to agree that the drive train on most cars is pretty much bullet proof now. My expertise is Porches. To the pre 74 crowd's biggest problem besides rust is worn carbs or MFI, both of which can be remedied for about $1,500. The 74 thru 83 owners biggest worry is fuel pumps and parts associated with the CSI system. Pre 83 cars were basically the same from the beginning in 64. The 84 and later cars started getting all the whistles and bells. No driver of these leaves his driveway without a spare DME relay in the boot. Also, a very simple heater control system, using levers and knobs, was replaced by a automatic heating systems with temperature control, that fail on a regular basis. Prosche sells the replacement unit for 5 or 6 hundred dollars but the part that fails is a plastic ball socket. I sell, to the unfortunate individuals that have this problem, the door lock socket, which is the same size and shape but made out of metal. I guess Porsche wanted to make sure they would get 5 or 6 hundred dollars every couple of years out of each car. Otherwise, they would have put the metal one in the heater control unit. The later cars have even more funny little quirks.
(i.e. the Boxster, cruise control, it built into the main computer ) So when the cruise control fails you have to replace the whole computer. FYI--the best 911 to own would be an 83 Cab.