Since my car is a 1992, I had to swap out the tail light assembly so that I could use a one piece tail light blackout.  I was able to get an assembly from an '82 Trans Am at a local salvage yard for $20.  Changing the tail lights was pretty straight forward.  The wiring harness for the '92 was a little bit different than one that would be used with an '82. The turnsignal bulb sockets had to be replaced so that they would fit with the '82 style tail lights.  Also, on the '92 harness there were a total of four smaller bulbs that were not used. 

Other than that, installation was pretty easy.  I then painted the reflectors on the bottom of the left and right pieces black.  I did this so that the reflectors were not visible through the black out I had purchased.  I got my one piece black out from Don Colie of Advanced Designs (ADiAT).  Pictures below...