I had 40s on my Bronco with big tips and they were very loud. I ended up switching to 50s so I could hear the radio. On my mustang, I ordered but have not installed yet the Flowmaster super 44 exhaust kit headers back. From what I can tell, they are more of a muscle car sound verse what I think of as a fox body soundwith the 40s.

 

Just installed my flowmaster
40 kit yesterday.
Have the same ones on my wifes 04 gt .and love them.
Somehow they dont sound the same on my lil 347. Side by side you can barely hear her car.
Sounds evil chugging and growling. Sounds almost like the open header as far as depth just not as loud.
Nice fit on the kit I did have to fab up down pipes to the H pipe tho from my shorties. Those are not included.