Wrapping a car - educate me

[Mr Gearchange]

Chaps,
I'm currently car shopping for a current model RS6 but as I'm a picky sod it's going to be tricky to find exactly the spec I want on the 2nd hand market.

I'm considering that I might buy a car that has the spec I want - but not in a colour I want and get it wrapped. Certain RS6 colours seem to be 2-3k cheaper than similar cars in different hues.

so a few questions..

1) How much should this cost - ballpark
2) How long should it last?
3) Who are the most reputable companies to do the work
4) Do i need to treat the car any differently in washing it than a normally painted car?

Thanks