After some research I found "Vibration Proof Washers" and just had them installed on my Superformance sidepipes. They are manufactued in Sweden by Auveco products. The 7/16" size are Auveco #19284. Here thay are referred to as Nord Lock washers. Check
Maximum security for bolted joints -Home - Nord-Lock. Here's a video demonstration
Nord-Lock Demonstration Video - YouTube. Hopefully this solve the problem.