1980 was a change over year with the engines , you are right about that. And I am not sure about the rest of the world , but here in Canada you could still get a 4 speed trany in 1983. There are a few 5 speed E21's around , but not nearly as many compared to the 4 speeds.
I am not too woried about the 1979 injection system as it will be getting a full rebuild even though it still runs nicely. As for the other 2 cars I have never even tried to start them. I was told that one needs a fuel pump and the other should run , I just haven't had the time to tinker with them as life is very busy for me with my second child due any minute now and haveing to build my house & garage this summer while working 14 hour days. I also have a 1990 325i 4 dr That I want to fix this summer as an ocasional driver as I am sure the gravel roads will not be easy on it.