Had new Ford GTA axle back mufflers, bought from Blue Oval Industries, installed a couple of months back by a local muffler shop. Took in the other day to dealership as exhaust pipe was hitting frame over bumps. They said they fixed under warranty (moved main exhaust pipe some before mufflers) and said, "By the way, looks like you have a loose baffle in one of your new mufflers that you only hear when it gets hot." I bought this car new in Jan 09 and they only have 4,000 miles on them. Anybody ever hear of this happening??
it is possible with other brands as well. like said above, see if the company will take care of their customer.