I used a product called B-Quiet Ultimate which is essentially the same thing as dynamat but significantly cheaper and I can definitely say that it worked. I put it in to enhance the sound of my stereo rather than to block out exhaust noise but it has certainly turned the volume down a bit. As far as drone is concerned, I don't have any with the Borlas so I can't help you there.
I will warn you in advance though: it is a PITA to install... Climbing into and out of the tiny trunk a thousand times was not my idea of fun, but maybe that's because I'm 6'5" haha