@alfaromeoblack
You're in for a treat when you drive an early S2. I'd call the early S2 a sports car. Light weight, basic features, great motor, connection to the road and huge fun factor. The S4 is close to a GT, with power steering, more weight, softer ride, more creature features and more isolation to the road.
I own a few of these and they're all very special cars. As Alfa moved from the early, pre-smog S2's to the smog equipped S2 with more weight (heavy bumpers) and SPICA, then to the heavier S3 with Bosch FI and finally to S4 with even more weight, newer Bosch FI, bigger wheels and power steering.
When I jump into my 1973 S2, it feels more spartan. The motor feels angry! The exhaust smells like an older European motor. Everything manual and the car has such a hand on feel! You always know where the tires are - a true drivers car! Then I jump into my 1980 S2 and ... it's there, but much of the excitement is gone. Then I jump into my S3 and it just sits there (it's still at the mechanics shop!). Then I jump into my 1992 S4 and it's a completely different car. Much quieter with lots of soft surfaces and noise abatement.
I tell people that I bought my S4 for one reason. When I drive my 71, 73 or 74 (when it's restored), I worry that someone is going to steal the car. So, I wanted to have an Alfa Spider that we could drive for a fun weekend or just a trip to the beach and not have to worry about it being stolen - and if she were stolen, I'd have a much easier time finding a replacement. The S4 is just that car. I like the more modern look and the creature comforts. Power steering is nice when parallel parking. And the seats are definitely more comfortable. Sure, I feel the extra weight and the angry motor is gone. The motor sure doesn't breathe as well, but the VVT does help compensate. I bought her for a specific reason and she does the job perfectly!