Blkpr has the best advice. I actually went through the same route somewhere in the life of my 911 ownership. Coming from a 140 s class this car was dammed noisy. I put up a thread similar to this too. In the end I realized what a 911 was. To the op, all our brothers here are sharing their experiences with you, as I am. Though most are trying to desuade you sometimes sounding funny, they are still actually sharing in an effort to help you in your quest for your quiet porsche

 

I test drove the 2014 991TT and the rear tire noise is not there.
What changes were made on the 991 vs the 997.2 to stop the noise?
I suspect changes in the plastic wheel well arches or possibly rubber isolation on the rear top mounts for the rear suspension as opposed to metal on metal interface on the 997.2.

Please post photos and changes on the 991 that we could adapt to the 997 without the weight penalty of the dynamat.