I purchased the AVH-X4700BS. Do I have to use the Pioneer camera? ND-BC6? Are there cheaper alternatives that also flip polarity, show backup lines, turn on when backing up.

 

I was think Pac might make something or something on ebay.

 

This one seems promising but I'm unsure if the intended features will work.

http://www.ebay.com/itm/PIONEER-AVH-X4700BS-AVHX4700BS-COLOR-MINI-BULLET-REAR-VIEW-CAMERA-/181653489895?pt=LH_DefaultDomain_0&hash=item2a4b6448e7

 

Also, I have a 2000 Audi A4. Do I have to run a special reverse line to the OEM harness? How will the HU know when my audi is in reverse?