The motors come with gearboxes that I bought, I didn't realize the description calls it out as 1 wheel drive, odd cause it's definitely 2 wheel drive. This is what I purchased, I have no idea what to expect. I do plan on wiring in a second battery in parallel for longer runtime. Are you able to use the existing charging port to charge both batteries? I haven't looked that far into it yet.

550 30000RPM Gearbox with 12V Motor for Power Wheels, RS550 12 Volt DC Motor High Speed Match Children Powered Ride On Car https://www.amazon.com/dp/B072F7QWBQ/ref=cm_sw_r_cp_api_i_Q078EbJG6XBNV