from the GCIA website:
WSB-TV Consumer Investigative Reporter Jim Strickland presented a good story on the problem of inferior aftermarket parts and how insurance companies are forcing body shops to use them. See the video story - click here or http://www.wsbtv.com/news/news/local/car-repair-parts/ngZws/
This report interviews several consumers as well as Atlanta area body shop owners about this serious safety issue. The consumers appear shocked and dismayed.
The video shows some good examples of the difference in the quality of the parts (with the aftermarket part showing the CAPA sticker as the reporter flexes the reinforcement.) This video might serve as a great tool to address your opposition's speaking points.