PakBMW,
The pictures on the BMW brochures are from a 4.8 which has a Titanium kidneys rather than the black ones on the 3.0. It is not painted to match the car colour, it is titanium irrespective of the car colour. Getting it painted is a fairly straightforward job I would think since the two parts can be removed they do need to be prepped tho $500-600 sounds toppy.
The alternative is just buying the BMW part Titanium ones for $200 since your car is space grey, check this
thread. Then you can experiment with your black ones and see how the painting works out.
C