Part numbers: 51-21-8-399-239 51-21-8-399-240 Cost: less than $15/side Tools required: "hook" tool
You must "unlock" the stock door handle surround to remove it. First, open the car door and remove the black plug at the top of the end of the door. Use a thin-bladed screwdriver or an ice pick. You'll probably chew up the plastic plug a little bit--that's ok, just be careful not to scratch the paint on the door end.
When you look through the access hole, you will see a lever. Push the lever forward with a "hook" tool (picture a screwdriver with the tip bent so you could hook something with it). You will need to push firmly. This will slide the lever forward and unlock the outside door handle surround.
Once the lever has been pushed forward, the handle surround will be loose at the top. Use your fingernail to pull the top of the surround away from the door. You should then be able to lift it off easily.
The surround has a gasket on the back of it. Although I could not discern any visible difference between the gasket that came with the surround and the one that was on the stock black surround, the new surround didn't quite fit with the gasket it came with. The gasket lifts right off the surround, so you may wish to use the originals from the doors with the new surrounds.
To install the chrome surround, slide the bottom tabs into the marked holes and then push the top towards the door. Don't force it--it should go fairly easily. Then, use the "hook" tool to pull the lever back towards you--this will take some force, and it should lock down the new chrome surround.
That's it--you're done! Enjoy the new look!