Usually they will also sale just the muffler that they use in the kits. Might sound good on the mazda? Also, I traded in a Dodge Ram Hemi for the cx-9. The one thing that sold me was the take-off and stopping performance of the cx-9. I did not feel it to be under-powered. I have the 2007 and Im somewhat bummed about the 2008 3.7l but completely satisfied with the performance so far. A little sound would be nice. Not rice-burner loud but a little grumble grumble from the duals. Anyone else heard of aftermarket mufflers for the 9?