RB
I used a rubber extension on mine also. Mine seems to hold on pretty good with just the zip tie. I did ruff up the tip of the exaust though with a little piece of sandpaper to help it grip better. Another thing I have seen done to is to tie the extension off to something that restrains it from moving forward or backwards. Something else I am going to do to mine that I havn't done yet is to attatch a steel fishing leader to my exaust, and then attach the other end over to the firewall. This is just a safety wire to prevent the muffler from falling out of the Plane should it ever come loose. You can see my extension hanging down in this photo. Something about that last sentence just don't sound right! I should say, the Planes extension, and not mine.lol