I installed a D3 in a '06 Jetta, many thanks to this forum, I learned a lot here. I used a standard wiring harness instead of a CAN-BUS adapter, such as the CARP. The only thing that doesn't work is the Retained Power Accessory function, but I can live without that.
I used the Metra dash kit, but I'm not impressed with it. The Double-DIN side panels came unsnapped when inserting the unit into the dash, so I'll probably replace it with the Scosche.