I'll bet it uses 4-5mm mounting screws. Those wires in the back that switch the winding configuration-they switch between wye and delta. The wye should have more torque and be more efficient.
EDIT:
You can get 8mm pinion gears at
http://www.sdp-si.com
I picked out a nice mod0.5, 8mm bore, 20t gear:
https://sdp-si.com/eStore/PartDetail...32&GroupID=591
SH Z-Car, Custom Crawler, 8s Savage,
12s XTM XLB 1/7 buggy,
4wd 4-link rear/IFS Pro4 truck,
Custom Hyper 10 Short Course,
Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz