Yes, rust is an issue with this shell I acquired. It also has been repaired and repainted in the past. There is a lot of bondo on the cowl, and rust bubbling up in random places.Absolutely; the facelift from Series 1 to Series 2 appeared in May '82. Besides trim updates etc. there was a major change in the backbone technology as the Series 1 was still based on the E12 while the Series 2 used suspension parts, engines, etc. from the E28 (very simplified description).
I had two Series 1 and two Series 2. Were about to buy a Series 3 but that did not happen.
Very nice cars, but especially the Series 1 is comparable to the E9 when it comes to rust problems; at least in ny experience...
The '78 that I'm restoring spent its entire life in GA and SC, so its very rust free. The problem with my doors is the multitude of little dings. Given that I want the mirrors from this car, the glass is good, the doors are ding-free, the exterior trim is good, both door handle gaskets are intact and I'll be swapping the door cards, I might just change the locks and swap both doors from this car.
As to the seats, alas the Series 1 cars did not have the recaros, but instead had flatter wider seats that are very similar to the coupe seats.