Need help with my G3-build

[JoFreak]

Little update:
As the Bigmaxximum has a 3mm muff(?) on it's front, I designed a sort of 3mm spacer for the rest of the motorfront because I wasn't satisfied with the overlapping of the pinion and the spur gear resulting from this muff.
Furthermore I ordered some shims from a lokal nitro-truck-shop (will most likely be the only thing I'm ever going to order there) and some dogbone springs and HB output joints from tower (because german dealers seem to think they can rip me off and demand three times the price) because I don't like how the 8mm drive cups are fastened on the hb pinions.

When all those parts arrived, I'm going to disassemble the whole truck and rebuild it again but with threadlock on the metal on metal threads. And I'm going to seal the hybrid bulks with Dreibond. So the diffs should stay free of dust and generally any other kind of debris.
Dreibond is like silicone for sealing purposes like in a bathroom but it doesn't get that sticky and is easier to remove if you need to, great product I know from my years as car mechanic

Finally a short question: Do FLM diff cups for HPI Savage diffs fit with the Hot Bodies diffs? I thought, since HB is a part of HPI, the parts might be 100% compatible.