G3R - What trans ?????

I would like to know is there any benefit to switch from G1 single speed (already out of stock, IIRC.)to 3905 transmission? Lower CG? However the adapter will gain some CG. height. Better slipper clutch? Yes, I think it is better unless with the modification of G1 with Revo-spec slipper. Any other else?
I have a G3R, too. I am thinking about the upgrade of the transmission.