I found that the sanding cylinders on the rubber wheel thing worked well at removing the black powder coat. The PITA bit is the left hand side end of the aerofoil detail.

I used car spray from the local Halfords for the facia, Ford Nimbus grey I think. I have never had problems with these on plastics (funny, I used to spray everything in black satin, now I spray everything silver ???). I do think that the laquer is most important though. I did not do a coat on my first try and the paint rubbed off after a few months..... We will see how this one lasts.

I believe that you can get a special primer for plastics (for bumpers/wing mirrors etc.) but I have never used it. Anyone else ?