Hi Max!
Thanks to your help. I like the ball diff since it is a breakthrough to have diff oil in it. It is so smooth that I feel it helps on corner exit, compared with GD1. However it has an issue of oil leak at the case (AT01/AT02). Will try to get GD2. I run modified with X22 10.5T or X20 8.5T.
I have a mod on the RFG to let it float more. It helps me a lot on the real grip. Any other mods to share with us?