hey just got my a3 and theres a problem with the radio volume, it stays at the same volume but if u turn the little knob it will either go full blast or turn off completly. is there any fix for this???? if not i have my own cd player that i can fit i know ill need some sort of fascia but is there anyway of keeping the display of whats on the radio etc on the dash where the temp, miles left etc is??? and could i still use the cd changer with this?? i also have a sub and amp i could fit if wanted, would i have 2 disconnect the standard audi sub??