I've got one of those Flowmaster Am. Thunder mufflers made espec. for the V6 'stang on my '06 convert., and it really drones at certain rpms. Can anything short of replacing the muffler again be done about "the drone?"
I'm sure it would make a difference.
The reason I chose the areas I did are.. when I tore out the rear seat and side panels, to install the SHR Louvers, I noticed that there is next to no sound deadener or insulation in that area... Then when I installed the Pioneer DVD/NAV I noticed that, again, there was no sound deadener or insulation under the center console at all. Just very thin carpet. So over the next couple months (I did it in stages) I did what the factory should of done.
There are acouple stores on Ebay that will put up good deals on bulk packs of dynamat extreme. Just keep your eye out for them and make sure it's the actual Dynamat Extreme.. not a product that they are describing as being like Dynamat.
Ditch it for a OEM GT muffler ...
Okay, what I done is put B-Quiet Extreme under the removable trunk floor, i.e. the spare tire cover and on the thinner exposed parts of the underside of the trunk lid. I've also gotten a piece of carpet padding 1/2 inch rubber with a vinyl like covering on one side, cut it to fit, and just layed it over the spare tire under the cover. The result is that while the "drone" is still there, it's only about half as loud as before and much more tolerable. Am going to attach my left over B-Quiet Extreme to the bottom and sides of the spare tire well soon. It has made a noticeable difference for the better...