I was thinking about getting some type of high flow cat to replace the stock one on my 08 4.6. I have a Roush muffler and planned on keeping it on. I'm not looking for a horsepower gain and anything like that. Just a good sounding truck. Should I go through with this?

 

It really isn't going to make it "better" sounding, but it will be louder. Quality of tone comes more from the muffler. If you do want to make it louder, two Magnaflow 94106 s and you'll be good to go.