I have a 2010 Mustang GT premium 5spd. I know I want flowmaster axle backs but not sure which one to pick. This is my daily driver that I race in autocross and other events and originally I wanted the American thunder axle backs but I have been hearing people talk about the american thunder CLASSIC ones that have a more aggressive sound. Will those be too loud? I want something that is aggressive when I drive the 'Stang hard but doesn't bug me TOO much on the highway/interstate. What do you guys think. I don't want to get the regular american thunders and wish they were more aggressive?....Thanks

 

I have the Thunders on my 06 GT and I love them...I was amazed when I had it on the Dyno...how good they sounded...What really made them better was running my Brenspeed 93 oct tune...they sound very much weaker with an 87 tune...

 

No muffler is too loud with stock cats. But, if you remove the stock cats then muffler choice becomes more critical for noise levels.

 

Thanks. I think I am going to go with the American Thunder Classic system unless I get more info.

 

I have been reading that the stock clamps are better than the ones you get with the flowmasters. Is that True?

 

I have the Quieter Flowmasters not the Classic and like the sound after they have been broken in.


http://www.youtube.com/watch?v=IKX2XaxkuRc

 

The regular FlowMasters sound pretty good ... I was thinking about going with the Classics but if they are too loud and drone I would not be happy ...

 

On my 2001 Mustang GT I had flowmaster super 40's and loved them. Do you guys think the regular american thunders are close to those or the classic ones? I am with you on this one dmhines on not being happy if I got the classics and were too load with too much drone. I keep changing my mind back and forth between the two.

 

Larry2014, are those the American Thunder axle back on your car? They sound good. Do you have any "bad" drone with those or is it minimal.

 

yes, they are the American Thunder axle back mufflers. They sound pretty quiet inside the car with windows up driving normal but get on it they sounds great especially with window down. The drone is not bad at all and I have the 373 gears.