I get regular compliments on my 85 911. It is "mostly stock" but some subtle upgrades. The AC simply works in all conditions. The heaters are stock and astonishingly good. The suspension was rebuilt with new rubber bushings, and some minor upgrades like turbo tie rods.
For a 40 year old car, it is just my perfect car. Modern enough to be comfortable, and fun on a race track or autocross, or long 12 hour day cross country drive. And it looks great.