I KNOW !!! My red one on my truck sounds like an air compressor, and I never noticed the one on my '27, probably because the exhaust is so loud.

I mounted both on rubber, but still loud. Someone on here posted a while back that you cut up the rubber straps that come on muffler hangers and use them as isolators, and I am going to try that. But I'm not sure if it is vibrations or just internal noise, because my truck is getting louder all the time.

But the upside is, at traffic lights it makes the guy next to you think twice.

Don