Sorry I don't revisit this post often. I don't know if the muffler on the new GT2 will fit your GT3, you'll have to visit the dealer and ask the parts guys. Of course the two engines are similar but also different in that the GT2 is turbocharged but the weight is half that of the regular 997 turbo's muffler. This new muffler is made of titanium like the Corvette C6 muffler and is lighter than the stainless steel ones they use to use. As for sound I have no idea what it sounds like.