I'm thinking of using some insulation to kill some slight exhaust drone I have.

I've heard that putting insulation under the back seat, and bottom of the trunk helps a lot, anyone else? I have reflectix, the metallic covered bubble wrap that i would use..

I used some neoprene rubber (big pieces I had to cut to fit). I'll bring them along to MAG and we can toss them in to see how well you like them -can't say I want to get rid of them just yet, but I may be able to get some more of these neoprene strips.
I had one piece under the back seat and on across the trunk, directly above the muffler. I definitely noticed a difference when I had them in my SLE with the Magnaflow muffler. They are about 1/4" thick and just drop in place -not really secured.

i doubt reflectix would do that much, maybe get something to put under the trunk carpet? You would have to be able to lift it up to get to the spare tire, so I am thinking non-attached.

Another idea is to get some of the spray cans of rubber and spray underneath the trunk above the muffler, though you would probably need to take the muffler out and spray a few coats.

Jseabert and I both used thick household carpet padding. Enough to do both trunks was about 15 bucks as I recall. I paid, he cut.

Worked like a charm, but after the resonator install, I don't think I need it any more.

what about if you had 2 mufflers of different sizes, would that cancel out the drone?

Yup, GTO'* have this setup stock nowadays. I only have one muffler though...