I am in need of some advice. I am researching too but thought I would post here in the meantime as it should be fairly easy. Due to lack of funds (and decent past experience with Xtrons), I opted for a clone of the Xtrons PF71A3A. It was touted to support Bose and as it was designed for the A3 I thought installation would be easy. I had read of others having problems but that was some time ago and this came with 2 ISO harnesses so I thought that must have been resolved, it appears I was wrong... My car uses the quadlock, here is an image from another thread, mine is the same except it is missing the yellow/orange connector: Now the adapter that came with the HU looks like this: Note the green and blue plugs have nothing to connect to! I imagine they must do some pretty important stuff... There is also 1 pin on the black section missing from the harness. I have 3 spare wires on the harness labelled: GND KEY1 PANT I imagine the ground is supposed to be for the handbrake so video cannot be played whilst the car is in motion, where am I best wiring this to? And where do the other two cables go? I am fairly good at wiring but don't want to cut or change the OEM cabling, I'd rather buy another harness and adapt that so if I wanted to I could go back to stock. Also the radio cable in my car is a double but the radio antenna ISO adapter only has a single connection, does it matter which I use? Is one just an amplifier or digital radio? Just teething problems and also I am sure you all know the best places for earthing etc. I could find one myself but would rather listen to experienced A3 owners Thanks P.S. Is there a wiring diagram for the quadlock anywhere so I can work out what each pin goes to myself?