The easiest way that I can think of, would be to type in text, or bring in a image as a layer, and just lower the opacity till its just barely visible.
'09 E92 335i (6MT) Jet Black/Coral Red
'11 E90 328i XDrive (6AT) Jet Black/Saddle Brown (wife's car)
'06 Evolution IX MR (sold)
'06 R6 Anniversary Edition (sold)