Originally Posted by SteveM

The local guys use the Tamiya one-way in front and solid rear diff on their TT-01 cars.

There isn't a motor mount that I know of that lets you adjust the gear mesh. If you use the stock Tamiya spur gears you must use the Tamiya 06 module pinion gears, and there are only a few gear ratios you can choose from.

If you modify the spur gear adapter from the Tamiya FF-03 you can then use any 48P or 64P spur gears. You have more options to set the final drive ratio but you're still stuck with the non adjustable motor mount. I recommend the Tamiya aluminum motor mount as it's a more precise fit than the stock plastic one.