I have Mac on my 08 GT/CS. IMO Magnaflow are to way over priced and don't sound as loud. The Mac's do have some drone going through the gears or getting on it but once your cruising it goes away.
Neither!!! Got Magnaflow on my 07 GT/CS no cats, OR x pipe & factory manifold-bought that way. It was gonna be my project car. It's so loud but throaty & raspy. I just put Roush axel backs on my 11 Coyote-all stock aside from Steeda CAI. Best tone & quiet cruising to loud when foot on pedal to wot. I kid u not-EVERY One gets neck whiplash when I step on it. Unique best tone ever. Spend the money $531 free ship from AM & super easy install-promise u will love or u don't know what a Muscle car should sound like. These should be stock on every Mustang but glad there not, love the compliments on how superb sound quality I get daily driving or out for a romp around town. Coolest is when u let off they go to better than muscle car tone. 5+ stars