I did it with my cousin on his Chevrolet beretta gtz. We didn't know what the truck we were doing but we made it work.
t seeems like our bonnies' lights are exactly like the beretta (good assumpition since its all gm) anyways all we did (and subsequently what i recommend you do) is to remove the tail light housing.
Then with a screwdriver (see what size is nicest for you, i guess a smaller one would be less likely to crack the housing somewhere but a big one gives you more power. Anyways disengage the tabs as well as running the screwdriver through the black glue that holds it all together. Then with some gentle prying open up the whole thing. Took us all of about one day but it was fun. With the housing open you should see the reflector atached to the outside part of the housing. You can pry this off easily too. Now you can put it all backtogether without the reflector or you can do what we did
We used some PVC pipes and painted them silver and fit them around the holes where the bulbes are supposed to reside. Then we put a reflector at the end of the PVC pipe that shows towards the outside of the car. That way it looks nicer and makes red light out of any white light bulb.
In any event when you put it back together make sure you use lots of adhesive to keep water from getting in. I recommend something like "Goop" but stronger if possible. RTV Sealant might be a great choice too!