I just did mine the other day. Cleaned them down with a wire brush and gave them a good de-grease! Paint I used howevver was halfords own engine paint (red obviously). Stuff realy did the trick. Too a long time to dry and it looks great. Gave it 3 coats mind you just to make sure all is sealed.
Put this on my old Leon Cupra TDI and it lasted forever and stayed shining. Only £6 a tin aswell.
Thanks
Kevin