Almost anything is going to change the way mufflers sound. Stock engine, vs modified, cubic inches, pipe diameter, crossover, muffler size, etc.
what may sound good on one car, may not sound good on another.
Numerous independent tests have shown, that flow masters, actually don’t flow very well.

My car. 526 stroker, 3 inch exhaust with dynomax ultraflows, no crossover.

https://m.youtube.com/watch?v=2d7zHk40Rhs

https://m.youtube.com/watch?v=XoXBvRqJuyk


526 cubes of angry wedge, pushbutton shifted, 9 passenger killer!