[drb930]

While its hard to add to what has already been said...
I currently have both 964 C2 & 993 C2S.

The feeling of how the 964 bobbles over the road & bumps feels much more early 911 to me as it is still on trailing arms in the rear.
The 993 are so planted in the rear that it transforms the feeling of the car from early 911 to a more modern driving experience than the 964.
If you look back to the 993, through 996 & 997 & then forward now to the 991 the basic suspension "design" is the same although much more refined.

The 964 is the same chassis as the 993 except for the rear suspension and bonded glass which brought the stiffness of the chassis up another 20%.

I really like the balance of the 964 vs a G-body car as even stock 964 can handle much more predictably than a G-body... as the 964 has a much better front suspension than G-body and redesigned rear trailing arm suspension plus all 4 corners on coilovers from the factory.

You can't go wrong with either... I think 964 values might surpass 993 as 964 were the bastard child when they were new and are just now being appreciated yet many were unloved, turned into race cars, and now Singer's ect. so the numbers are becoming lower for basic stock examples.

I will say it is very frustrating the build quality of both compared to the last of the G-body's circa about 1988. You can start to see Toyota's influence starting at that point. The use of plastic in both 964 & 993 is terrible compared to the hand-built's up to G-body.
Although 996 & 997 are worse in the use of plastic!