You want some wet and dry. Get some fine and some rough.
Sand the bumber strips smooth with the rough, then touch it up with a finer paper.
Doesnt matter what paint you get if you want it colour coded or what..
Primer About 3 coats, after each coat let it harden up, dust off with a fine wet and dry just to smooth out any imperfections
spray your colour on, again 3 coats or more. DONT go right up close with the spray, lightly dust it with the paint.
Lacuer you want 2 coats, again lightly dust it on, you dont want lacuer runs..
Remember Preperation is the key to a good finish!