I have a 2008 Road Glide. I am NOT mechanically oriented, so I'll say that up front...

I was involved in an accident (not my fault) and the insurance company replaced most of the stuff on the left side of my RG (inner/outer fairing, left saddle bag, all the chrome, and the left muffler). Note that I said the LEFT muffler. They left the older right muffler alone.

The new muffler looks slightly different and I can tell it sounds different from the old one. Both are the stock HD mufflers as I've never upgraded the old ones. I'm not interested in replacing them with non-Harley stuff, btw.

I need to make a winning argument to the insurance company that if you replace one, you should replace them both. Other than looks and sound, are there any mechanical justifications I can use? The original muffler has 55K miles on it. Will this affect power, reliability, engine life, etc?

Thanks for any tips!