The director of Tian Siang Premium Auto fitted this to his 523i as a show model for anyone interested to see. The wires are routed thru the inside of the seat in between the rear moulding and the cushion, so the cable will not dangle on its way down to the power supply. It emerges at the bottom, where the two cables from each monitor is joined to a splitter box (round in shape). One power cable and adapter then connects the splitter to the rear 12V socket.
Quite neat actually, except placement of the splitter box, which is about 2.5 inches in diameter, might be up to individual taste.
The size of the LCD is quite acceptable, and you can connect the device to the car's audio system thru the aux jack. However, this jack is available on the 523i at the rear and not on the E90. So I guess using the built in speakers or wireless headphones is the way to go.
The SC in Ipoh already sold 6 units he brought in and he is bringing in another 10 units. Seems like the thing is selling like hot cakes. Have booked mine too BTW...:biggrin: