Any feedback on using copper exhaust donuts?

[1970mach1]

Hi there, I am in the replace the exhaust donuts phase of my 07 Attak. I have looked at the copper donuts and they sound good, but is the connection between the donuts and the exhaust too rigid and will it cause more damage?? Any thoughts and or comments are appreciated

 

[Vandelay Industries]

http://www.ty4stroke.com/viewtopic.php? ... er&start=0

 

[scar]

Just installed a set of copper donuts.Think they should be just fine.Alot of fun doing that install.