seems like for a flowmaster to be good, you need to upgrade to 2.5" pipe as well.

 

When I did my exhaust the first time I just replaced the cat and muffler with magnaflow pieces...it sounded good and was not to loud but you noticed it...Not too long after that I did the exhaust on my buddies jeep..we did a header, new downpipe, magnaflow cat, flowmaster muffler, and a new tailpipe...it had a real nice deep tone to it and was a bit louder...I liked it so much that I ended up changing to that set up about a year later when I had to replace my downpipe. I def like the flowmaster better.