Does anyone know where I could find an external GPS antenna that somewhat resembles the antenna's on the newer BMW's? They look sort of like a shark fin.

Also, regular car paint won't mess with the GPS will it? I'd like to color match it so it looks like it belongs on the car.

EDIT: I found where to get the shark fin, thanks to VWmike

The shark fin is a factory VW part, P/N 1K0-035-507-C
That still doesn't answer the paint question though.