You are welcome. Again, I would just keep it stock, but with first motor that I recommend, 2600kv on 3s it will be significantly faster with original pinion but it will not destroy your car. You can run 2 3s batteries in parallel for a lot of run time.
That car could be fun driving on the...
That's an oldest generation of emaxx. I have one, paid 100$ for it. It's a two speed.
I would highly suggest to keep it stock or if you convert it to brushless to go with very mild setup. Those cars are not designed for brushless power and if you put anything higher than 3 s you will destroy...