God damn it, everytime I chuck it in reverse its acting like there is someone standing behind...

Its over-sensitive/obviously faulty but no fault codes registered...

There are 4 of these little blighters... so its trial and error... couple of dumb questions:

1. Are they expensive?
2. Can you get them ready painted from Audi or some place?
3. Common fault?

I only ever really use them to reverse as close as possible to the rear of the garage wall (small garage).