I see here that nobody had the idea to remove entire NFS module. Its just glued on the back of AMOLED. Just use 100ºC from some distance with air station. Just remove from s3 and put on s2 lcd (or vice versa). Job done.
We can see 3 connectors.
1- first one is the LCD (same)
2- touch (exact the same in s2 and s3! just see the IC - its same IC in both models). Touch screen for s2 is the same for s3!
3- third module has some differences but can be easily removed and replaced.