I just ordered a r4ds for ds games, now what for gba games? Could I get a m3 perfect? and if so would the r4 work as a passkey even though they are diffrent brands? Or do I even need a passkey for only playing gba games?
You do not need a passkey for GBA games. Get an M3 Perfect and another microSD card. Save GBA ROMs on one microSD and NDS ROMs on another. Run the GBA ROMs using the M3 Perfect and NDS ROMs using the R4DS. microSD #1 [GBA Games] --> M3 Perfect (slot-2) --> NDS <-- R4DS (slot-1) <-- microSD #2 [NDS Games]
Oh, and also is the m3 perfect drag and drop as well. If I have the gba roms, are they pretty much all playable?
I'm not very familiar with the M3 slot-2 adapters. mr_hanky has written a wonderful guide to m3 though. Check out the M3 GBA ROM compatibility list for any documented issues with certain titles.
No, the M3 Lite Perfect is not drag and drop. You will have to run roms through a program to transfer them over (all Slot-2s are like this, as far as I know)