This.

 

Up until the 2010 model year the GT500 didn't have any special mufflers. They were the same mufflers found on the 2005-09 GT with an automatic. In 2010 Ford first put GT500 specific mufflers on.

 

Have you considered MBRP installer series axle backs? Although I am not nearly as modded as you, they do provide me with what I consider a deep throaty sound that I really like. NO drone. Not very much cabin noise although you can hear it when you punch it. Sound is subjective though.

 

Yup. They share the same part no. and I have them on my car. I'd bought them as used take offs.

 

I see people paying big dollars because they are "GT500 mufflers" or trying to get big dollars -- all for a part that came out of the stock parts bin at Ford. Just like people paying money for the "GT500 side skirts" which were simply the V6 unpainted side skirts. Attach the GT500 to it and people will spend the cash.