if you want "RWD" drifting you should run upto 200% overdrive.
it's the best way for now, it's still 4x4 but the rear wheels have more RPM.
works well, you can find info on
www.csjunkies.com
http://www.youtube.com/watch?v=RTx_5YNwpKo
http://www.youtube.com/watch?v=UNe3o75KmjA