Not too hard to paint them, but hard to keep them looking good. You will need plastic primer first to make the paint (satin black recommended) stick. Then lacquer. Problem is, no matter how well its done before long it will start to flake and look proper sh!t!
Better off just getting a decent trim detailer (back to black is really messy and crap anyway). You could try a hot air gun to restore the plastic back to original colour (beware you need to be very careful). Have a look in the detailing section, in the stickies, there is a bit that has reported the results of a few of them. Or you could use boiled linseed oil which apparently works really well.
