Need help with my G3-build

[JoFreak]

Update:
I mailed FLM about their Savage diff cups yesterday:
"I just wanted to ask if those diff cups (FLM44000) for HPI also fit the HotBodies Lightning pro diffs? Since HB is a part of HPI I think there is a possibility the diff parts may be compatible."

That's the answer I got today:
"Their is actually a difference. We do have a diff for buggy gears, but I cannot say for certain if it will fit the pro diff."

I fear this is no that helpfull information...