If you need to accomplish auto repairs on your Polini 911 GP 3 then it is usually a good idea to have access to a Workshop Manual for reference in the event you want to know methods to take out a certain component much like the Gearbox and install it again successfully.
Polini 911 GP 3 Workshop Manuals can provide particular diagnostic guides on your vehicle so if something is faulty it can help you understand what the problem is and some ways to fix it. After that you can determine if this can be done on your own or that the job is too big it is possible to book your 911 GP 3 into a decent repair garage.
Polini 911 GP 3 manual