If you choose to do fixes on your CPI GTR150 then it will always be recommended to own a Workshop Manual to use as a guide if perhaps you want to know simple methods to take off a particular component for instance the Dashboard and fit it again safely.
CPI GTR150 Workshop Manuals can offer you particular diagnostic information with regards to your automobile so if something is playing up it will help you work out what the problem is and ways to correct it. You can then decide if you can do this yourself or if ever the job is just too big you could book your GTR150 right into a suitable garage.
CPI GTR150 manual