subanez, I've found that EVERYTHING is twice the price in the UK...
I talked to a local body and paint shop here in Houston a while back and they said they'd do a proper paint job on a Porsche for around 4,000.
Proper means removing the door panels and anything else that needs removing to do it right. It's not just a "tape off the rubber bits and glass and start spraying."
To totally change the color of a car, it can cost a lot... they really should take a lot of the car apart to spray in the areas that few people see. Those few would be the mechanics telling the future buyer that it was repainted poorly