I have good news for you buddy: Only level of equipment varies between models, so higher-end model owners are the ones screwed by extra noise, since we had to pay more.
Now to your issue. Just traded a top-of-the-line Accord (a $31K EX-L coupe 6MT with Navi), and it was NOISIER. And not only that, it didn't have door sills, it had a hard-plastic rear deck, manual trunk and gas release, plain door panels, and many features not present on my 4-cyl Sonata. A lot of the tire noise has to do with cheap tires, but few of us feel compelled to spend on new tires on a brand new car, but when you switch, you'll likely find it quieter. Cars at this price point are all going to have similar levels of noise, with the possible exception of the Camry (for what I've read, but I've never driven one), but I much rather have a noisier cabin than drive an appliance like that, to be honest. Just crank the stereo a little more, and have the consolation that we Limited buyers have the same noise levels as your GLS. By the way, all Sonatas have a single muffler except the SE (by the way, there's a difference between dual exhuaust and dual mufflers; the SE has a single-exhaust like all Sonatas, but with dual mufflers).
Oh, do you want to feel even better? My M3 (the new model) is even NOISIER than the Sonata, and paid almost 3 times the Sonata. Talk about disappointment there. And no, I DO NOT have a tire choice; all tires available on stock sizes are the summer kind (a double whammy :grin: ), which are noisy as heck. Just crank up the stereo on rough roads and enjoy your new ride. Take care.