Never had anything rattle or loosen in any of mine and have never actually heard that. I have ordered 3 pairs of them in the past 6 years or so and also have a pair on my run stand exhaust to quieten things up when running in new motors. Those one are about 10-12 years old now and are still sound great with no rattles.
They do have these in stainless as well. Had the polished stainless 3" Aero Chambers on my 55
