As I have said in previous posts, I much prefer the S2 styling over the S3. That includes the interior. That said I've had the car for 25 years and doubt I want to take on the headaches of an S2.
I recently purchased a set of black S2 Door cards from Centerline and installed them in my S3. The fit perfectly. All the holes in the board line up perfectly.
Although the original arm rest door handles would fit and look OK, I also chose to use an original passenger side door handle from an S2 (ebay). It kinda looks like a 50's frig door handle. The handle was dinged up when I got it but, because it is solid aluminum, I was able to file sand and polish until it looks brand new.
I used a Triumph Tr4 door handle for the driver's side. It fits perfectly (same distance hole to hole), looks very similar to the original Alfa handle, and is $35 cheaper. (It's not a concourse car and never will be.) Instead of just using sheet metal screws into the door steel, I used nut certs (rivnuts) with stainless oval head screws. This made the handles much more solid feeling.
I think the pleats and chrome trim make it look much cooler and it's totally reversible. Herb