actually, there's not much difference....
basically what does change is all the memory addresses locations, so if you have a hack made for 0.3x R1 and you're using 0.3x R1-2 it wont work.
here, kye says that it was because of this that he made 0.3x R1-2(we know that this is bullshit, that's not the reason why he made this update a few days after release 0.3x R1, anyway...):
http://forum.sa-mp.com/showpost.php?p=2 ... ostcount=1
btw, yeah... 0.3x R1-2 uses a AC different from 0.3x R1, anyway, nothing that can't be patched.
also, 0.3x R1 is the "cheaters version" because FYP already has started the update job with mod_sa and sampfuncs based on 0.3x R1 engine, when 0.3x R1-2 came out, so since 0.3x R1-2 is basically the same shit, he just finished updating everything based on 0.3x R1.