The main difference between Polymer80 and this PSA, is cost. Tools and parts, you will spend about as much if not more on a Polymer80 build than a stock Glock. Vast majority of consumers are more likely to buy a Glock than build one. PSA is directly undercutting Glock. Like the Sigma did. S&W also didn't advertise that the Sigma could swap some parts with Glock. That nail in the copyright case was found out by consumers. PSA is either being brave from a business standpoint or came to an agreement with Glock.