Yeah what he said
I did mine myself but that's what I do for a living. I didn't bother priming any of it though.
You'll find you won't have to rub down the grill as there's not really any texture on it, I just used 1500 wet n dry on mine to key it.
Just make sure before you spray anything on it you clean it thoroughly, preferably use some kind of degreaser or you run the risk of the paint flaking off (one of my mates tried to spray his bumper with out degreasing and it all came off the next day!).
I also used a special adhesive to insure the paint stayed on, that was on my bumpers though. You can get most of this at halfords now I think. I wouldn't recommend doing big areas on your own as you really want sprayguns and a compressor to do a half decent job but you should be fine with your grill.
Definitely remove the grill though (there's only a few screws holding it in). Dunno about the badges as I have no idea how easy they are to stick back on. I expect someone will be able to help you on that one though.
Hope this helps.