You can buy the center diff conversion from rc-monster.com

Hi mate

I saw your conversion ( the My g3r build ),.. you have posted some very kul picsture about your conversion,... one of them show conversion kit with buggy centre diff, and the kit can have motor mounted upritte, on top of the diff,..

please let me know where did you get that kit?.. so i can get one for myself and have my truck converted

Thank you