does one of you happen to know the size of the individual loudspeakers and the corresponding installation depths?! and is it possible to install a Radio Concert 2 e.g. into the golf 3 without further ado?!? Or is it easiest and cheapest to retrofit the DSP?!? there are differences in the construction years from the connections, because it will probably be very difficult to find a complete system somewhere. and depending on how expensive that is, I can not pay all at once So m Do I have to pay attention to anything?!?