use automotive paint..or a REALY good clear. the elements are really hard on these speakers. I did a house Down at the shore were a customer wanted the speakers to match the houses cedar siding. I took a stained cedar board into the paint shop and they matched it the best they could. I had them pop the color in a spray can. Ive found that prevels dont have a very fine mist for this kind of stuff.

I plastic primed it, used adhesion promotor then started spraying them with 3 coats then did two coats of clear. The speaker grills i sanded, used self etching primer and went to work. for each coat i took my shop vac and vacuumed from behind to make sure all the holes were clear. Turned out beautifully. I wish i had backed up my old mac harddrive. I had some impressive jobs on there :(

Almost always i will have the customer provide me with a sample of paint, i then take it to my paint store and have them match it and put it in a sprayer. It gets adamized into smaller particles and lay down much much nicer. Prevels work good if your in a pinch.

So as followed:
Speaker Bezels -
Scuff up with Scotch Brite pad
Spray with adhesion promotor
Spray color

Grills-
Scuff up with scotch Brite pad
Self Etching Metal primer then vacuum from the rear
Adhesion Promotor then vacuum from the rear
Spray color then vacuum from the rear

Collect check! i charge 25/speaker + one hour to go get paint made up.

If i have to do an automotive type finish then its 89 per speaker + one hour at the shop

I have found that painters dont understand the the grills need to be open. I have also found that painters just take a foam brush to the plastic bezels which makes the paint lay down too thick and not as even.