The three chambers don't drone much. Most people think of the 2 chambers when they think of FlowMasters. On the flip side of that, the 3 chambers flow about as bad as the factory muffers. The muffler you have listed from Amazon is also not the correct configuration for a Mustang. The inlet and outlet are corner to corner on a Mustang. Flowmasters have a pretty bad reputation for rusting out pretty quickly. It's money poorly spent. My Dynomax mufflers are 20 years old, and look like new. I paid $140/each for them.