It comes with a 75 tooth .6 spur gear, and a 105T .4 spur is available as a hop-up from Tamiya
Thankfully they're not proprietary like the TB-02's spurs, and any spur you can find will work (within size limits), like regular 48 or 64 pitch.
What broke the camel's back for me to switch were the soft aluminum AV pinions they give you, and the limited gearing of the 75T spur. The fact I had 1/12th 64p stuff also helped.