Transmission for Traxxas UDR with Mamba XLX2

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Estonia, Tallinn
Hello All,

Maybe you can offer me some guidance for overcoming the challenge described below.

I am modifying my Traxxas UDR to be run on Mamba XLX2. Changes will include also full aluminium milled custom frame (3d printed now, needs several changes, model shown below) and gearbox (early days of development).
Now I am looking for a solution for transmission from motor to spur gear.

As motor shaft is 8mm, and torque will cause apparently some issues for 0.8 mod gears, ideally, I’d need 1.0 or 1.5 mod spur gear to replace original 8574. Plus, gear for motor and also a third gear between these two.
Equally, I can run it all in with 6S first and find pinion gear with mod 0.8, for 8mm shaft and ca 27 teeth. Plus, a gear between that one and standard 8574, which is easy-beasy part of the equation.

The challenge is, as you can imagine, finding suitable gears for either approaches described above.

Maybe, as an option, a whole central differential could be replaced but I am not familiar with other manufacturer solutions there…

Is there anything you can suggest me please to start with?

Warm regards,
Contacted WFO but still no response...
Are there any other suggestions, with what to replace whole central transmission?
Or custom-order a new 1.5 spur gear to replace original 8574?

This seems to be how WFO operates. I’m modifying an Xmaxx to run a Hobbywing 5687, so I purchased WFOs motor mount, receiver box, and ESC mounting plate for the Max 5 ESC. Nowhere does it say Mod 1.5 gears are required for their mount, but the mod 1 gears that I apparently wasted money on, won’t mesh because the motor won’t go low enough. I’ve reached out to WFO twice with no response, because I’d like to go ahead and order some Mod 1.5 gears and get this thing running, since the gears no longer show back order, but there’s no phone number to call, and they won’t return emails. Maybe it has something to do with the extreme smell of weed that came from the last package I opened from them.
I have emailed them 3 times with no response. Maybe they all caught covid and kicked the bucket. If they are still kickin, they don't seem to be someone I'd want to deal with.
I've emailed WFO myself with no response.