408 tested with 8 different Flowmasters

I've run the same 3" Flow 30s with an x pipe for 10 years. It's pretty loud, but also a race car. Had Super 44s on my old 318 truck. They were quiet and had no drone.

FWIW, I run quicker times with the mufflers compared to open pipes (tested the same day, same track, runs 15 minutes apart). Flowmaster haters can take that info for their research.