Servonaut motor help

[SHROPSHIRE LAD]

I have built a few Tamiya trucks and use them locked in 2nd gear fitted to a Carson Poison motor so don't need a gearbox with 3 speeds and use the gearbox servo for the steering. My next project will need more space inside the cab to fit the drive battery so I'm thinking of using Servonaut drive set. I have been on the Servonaut website and was wondering if a GM32U390 will do the same thing.

GM32U390 gearbox drive 7,2V 390 RPM 37x86mm shaft 6mm
built-in suppression capacitors
nominal voltage: 7,2 V
no load speed: 470 U/min
nominal speed: 390 U/min
nominal output power: 21 W
peak output power: 47 W
nominal torque: 34,6 Ncm
about 50% more power than GM32U370
dimensions: 37 x 86 mm without shaft; shaft diameter 6 mm

Is this a single 1 speed drive set which will match a Tamiya gearbox in 2nd gear with a Carson Motor ? and will my Tamiya 104bk speed controller fit or do you need a Servonaut.