If you need to execute maintenance tasks for your Polini Minicross X3 R then it is always a good idea to own a Workshop Manual for a reference if you need to know how you can strip off a particular part for example Wheel and install it again accordingly.
Polini Minicross X3 R Workshop Manuals will give you specific diagnostic information with regards to your car therefore if something is broken it will help you find out what the situation is and easy methods to repair it. You can then assess if you can do this on your own or that the job is simply too big you can book your Minicross X3 R right into a decent repair garage.
Polini Minicross X3 R manual