Yes the metal ring is wavy! I now have the x1 insert and its cut the sound back enough to not wake the dead or nearby neighbors. However it still growls and I like the way it sounds . The Px seems to have done the trick.
As for the slip on, I'm not sure of the details , I'm too new at this. I can provide some pics. I did take the chrome slip on off removing the 2 tension springs and a support bracket to clean it.
I so appreciate the good advice here! You guys have given me a solution that works!