Don't waste money in tuning parts. Just go for really needed parts. Prop shaft and bearing set are ok. Also a steel pinion will be a good choice.
The alu steering rack is not cheap and won't give you an advantage if you just drive around. I recommend a fan to cool the motor.

If you invest in a brushless set, keep in mind that the drivetrain has its limits. If you go stronger than 9.5t and run with highgrip tires there is a lot of stress and you will have to buy new parts.

For the tires: if you buy the standard competition outdoor sets from Solaris, Ride, Sorex or Volante the car will stick on the road. No need to pay the same money for Tamiya rims, foam and rubber.