So I went back by the shop and had them swap out the aftermarket res they put on the other day, and put on a "more aggressive" res. Drone is much more muted now. Its still present, but not nearly as loud and obnoxious as it had been. I'd say its only really noticeable under hard acceleration and the tone seems to be lower as well. Drone isn't fully gone but its at least at an acceptable level for now. May still end up getting a different muffler down the road but for now i'm content and it only set me back $65. As for back pressure increase, not knowledgeable enough about the inner workings of the res, but I couldn't tell a difference in the get-up-and-go department