I had an '81 base model liftback and can compare it to my current '03 CE.
The '03 easily outaccelerates the '81, is more fuel efficent, safer, and overall a better car.
On the other hand, the '81 handles much better, but doesn't have as much grip as the '03 (mostly a tire issue). Bear in mind that the '81 is rear wheel drive, which makes it an inherently well-balanced car straight from the factory.
Stock for stock, the better overall car is the '03, but if you decided to freshen up the '81 with a modern engine, suspension, and wheel/tire package, it will become the better performer.