I am thinking of getting black grills however I think I will also need to get the other silver bits blacked as well. What are those other bits at the bottom called?
I've sprayed the side indicators, which are pretty easy. Doesn't look 100% though, and the grill would (I imagine) be much more difficult to get an even finish on if using just a spray can.
Paint isn't cheap either, and by the time you've bought the sandpaper to prep, base coat, plenty of black gloss (you'll need lots of coats) and clear coat, you've probably not saved that much money - especially if it isn't perfect first time round and you need to do it all again...
If you don't have a dust free area to do the painting in, I wouldn't even bother considering it.