I think it needs a brace Artur. the plastic of the chassis isn't tough enough to hold that motor without flexing.

Thank you, I will.

It is funny, but I thought about the same thing and saved place to attach turnbuckles from motor bracket to ESC housing holes...
But if you look on the mount, then you will see that motor/idler/diff are locked together and other brace provides support...
But it would be nice to support motors back, I am working on it right now :)

New approach, any motor
 

Updated diff housing 4 standoffs and new motor plate.

Drawings were skewed alot :(
Better ones Motor plate Diff Plate with standoffs

will this version accept different motors and a different variety of pinions

Yes, from 12t-24t.
Motor Diameter is irrelevant now.
I will try to build a prototype next week and add some pictures with results.

thanks for adjusting to allow a different variety this model also appears to be stronger.