I am looking at two cat back kits from flowmaster - the outlaw kit and the american thunder kit. It states on their website that the outlaw kit has an aggressive sound and the American thunder has a moderate/aggressive sound. I don't mind loud as I had a flowmaster kit on my 06 with the muffler taken off so just pipe from the cat back, but when it says the outlaw kit is aggressive, how aggressive are they talking about? Here are links to both of them:

http://www.flowmastermufflers.com/ex...&category=0&kw

http://www.flowmastermufflers.com/ex...&category=0&kw

I watched the videos for both, but the video with the american thunder installed is on a 3.5L Eco 🙄

 

There are plenty of exhaust clips to listen to on Youtube...just search 2015 Ford F 150 5.0 exhaust. I've spent hours listening to them. I like the sound of flowmaster Delta flow 50.

 

I have the American Thunder exhaust and aggressive is an understatement. To be honest, I don't mind loud if it sounds clean, but both are far too raspy in my opinion. If I wouldn't have had it welded on due to the shotty clamps it comes with, I would have put the stock back on by now.