Question about Tamiya 110 Electric Ford Mustang GT4 Kit

You can use both, both battery packs fit in. They have the same external dimensions.
Here you can get an idea of the differences between the two technologies:
https://www.galaxus.ch/de...

Recommended (but not mandatory, the car is ready to drive without them) are the ball bearing set and the oil pressure shock absorbers (both available as accessories).
Tamiya TT-02 ball bearing set
Tamiya tuning part