Exhaust note is subjective to each person...with that said a "chambered" muffler like the FM 40 is the typical "muscle car" sound. However, drone, especially if pipes do not exit rear of truck, and cab exhaust noise for some is an issue. I find as I age this can be annoying for 99% of the driving I do.
The FM 50's are a little tamer. Spintech is also a chambered muffler.
FM has recently come out with the "FX" which is a straight through muffler like the Magnaflo and straight through Dynomax (not turbo) with the perforated straight through tube wrapped in fiberglass. I just pulled my 40's off my 67 Camaro when I put in my 355 with headers as the interior noise was too much. They have quite the nice note and are louder than the Magnaflo or Borla counterpart
here is a chart listing all the FM mufflers relative to how loud.
https://www.holley.com/brands/flowma...flowfx_series/