The absolute best stuff I have found for the "Black" two tone (which is actually a deep dark gray according to paint codes) on the bumpers and lower body on the Sport is the Satin Black $2.97-a-can knockoff Rustoleum spray paint at walmart. It goes on deep black and glossy, but eventually dries to a perfect satin finish, and with time and sun exposure eventually fades slightly to match the factory paint as well as can probably be expected for the price.
If you do a good job of cleaning the surface, including wiping it down with mineral spirits/acetone/alcohol prior to painting, and do it in clear, dry weather, the stuff sticks like crazy, and only chips from seriously sharp stones and stuff. A few coats is necessary to get sufficient rust protection, but that's what you'd need to do anyway to get a factory look. It works fine with no primer or clear coat needed, but I'd say a clear coat for the bumpers would make them look a little better, and probably closer to the sheen of the paint on the body panels.
If you do the job right by taking the bumper off and removing the plastic air dam and trim, then prep and paint, it will look as good as new when reinstalled.
You can probably do a nice job with a surface primer, color coat, and clear coat with the new line of Rustoleum paints, but I don't know that it's any better for the price ($5-7/can x 3), unless you wanted a different color or something.
Some Advance Auto Parts stores are clearing out their 11oz Dupli-color spray paint cans for $3.50 (which is being replaced by smaller 6oz cans at a high price), so you can sometimes find close color matches to the factory paint if you wanted to paint the bumpers to match the body, like a Limited.
Powder coating is an option, of course, and would be a slick move, but definitely expensive.
