rocky321

08 GT with stock exhaust. I like the sound of the Flowmaster American Thunder mufflers but not sure what to do with the cats. I would like to get a direct bolt in free flow cat setup. Which one? Worried direct bolt in off road straight pipes will be to loud. I do a lot of highway and don't need that racket.

ghunt

I'd recommend getting the mufflers first and see what you think...then think about cats. High flow cats aren't too far from no cats as far as sound goes, they're only marginally quieter. If you don't want the noise on the highway, you probably don't want high flow cats and you may not even want the Flowmasters. My car is pretty loud on the highway, I don't even think it's necessarily all drone, it's just loud.

09GT/CS

These cars tend to drone and be loud especially if you stay axleback its like it resonates in the trunk. I had my axleback kit cut up and mid mounted and the drone is night and day different. Its still there but much more tolerable now. Id say start with the mufflers and go from there. Cats can get expensive quick and unless you have heads and cams or a blower pushing more air by the time you get the tune and all in the performance gain may not be noticeable. Its not like the old days where cats were really restrictive they have come a long way in the tech side on that and the stockers flow pretty well for N/A applications.

808muscle

Exactly...stick with the axlebacks first. You can add an offroad midpipe later. IF you do go with one get the offroad H pipe, it has a nice deep tone, the X is very raspy. Flowmasters ATs are very nice, so are the Borla S types. Either one is a win.

Stoenr

Its really personal preference to be honest.


I had the flowmasters on mine, was ok, then went with cat delete, way to much.
Flows rusted out, put stock mufflers back on with no cats and actually was really happy.