I had a friend that works at Meineke install my turbo back. It sounds killer but he had a tough time with the down pipe which is still vibrating on something. It will be fixed, I just havn't had the time to bring it in. The power gains are also nice. From what I've read the Magnaflows are usually a tough fit on the 6.0s but give the best sound. Make sure the downpipe is not touching anything on the way down or you will be hearing a very annoying vibration as well.
Scott