Do a search, this topic was just discussed, and has been discussed several times in the last year.

If you want cheap ...

If you are talking about the covers, I was told by a good body shop that most aerosols are too "hot" for the trim and bumper covers. They look good after painting, but with time, the solvent softens the plastic and the paint peels easily. They refused to paint my trim for me!

In scale modeling, they use a product called "barrier" as a primer to protect the plastic from automotive paints.

Undaunted, I painted the front and rear bumper covers of out '95 855 base with Rustoleum. It has been on for two winters with about a half-dozen scratches on the rear cover due to loading stuff. All I did for prep is to wipe them down with paint thinner.

Color choices are limited, but I like the look - We have beige bumpers on a teal wagon. It stands out in the dealer's lot!

Volvo's special Cross Country has silver on blue.

Dress up your drab brick. Every car has body color bumpers, and most of them are white! Perhaps you could try a Rustoleun color as a primer, you might even like it!

One nice thing about painting your bumpers and trim - you can just wax them along with the rest of the car, no hassel with blackener products.

Let us know if you find something else that works.
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3 8s & 2 7s 740,000 miles total