I bought the basic P705 primarily to add a CarPlay screen to my old 911. While the screen quality seems acceptable despite a few software bugs, the P705's main problem lies in its poor faulty power supply. The result: a screen that flickers almost constantly and a completely unusable device. The unit lacks a buffer battery capable of stabilizing and maintaining a minimum voltage.
Power is supplied by a cheap cigarette lighter adapter that wobbles in its socket, causing poor connections. Furthermore, if your battery isn't fully charged (at least 12.7V) and / or if you plug in another device (your phone, for example), the voltage drops and the screen flickers. Another useful but defective feature is the FM transmitter, whose sound quality is deplorable, as is that of the built-in speaker; both are unusable.
The dashboard mounting system—unusable as is—deserves a more flexible system like Rammount.
In conclusion: avoid this device!