If you have to undertake fixes on your Polini 911 H2O then it will always be recommended to have access to a Workshop Manual to use as reference in the event that you need to know how you can take out a certain part much like the Drive Shaft and install it again safely.
Polini 911 H2O Workshop Manuals provides specified diagnostic guidelines for the vehicle so if something is not working it helps you identify what the issue is and some ways to resolve it. You can then assess if this can be done on your own or if the job is too big it is possible to book your 911 H2O right into a trusted mechanic.
Polini 911 H2O manual