I disagree about the sways. After a couple thousand miles in my 2.5T, I find the side to side motion and stability pretty well controlled in this car. I definitely feel the OEM all season tires hold the car back significantly when it comes to cornering. With the added weight from the 3.3, I could see the need for stiffer sways for the added front end weight.
I had sways on a 2010 camaro SS. At that point I realized how much my WRX swayed side to side, it was pretty bad IMO, but from there, it was hard for me to go "backwards" to something that leaned so badly. My BMW leaned pretty badly, even with the eletronic shocks. Some of the main reasons were that they did not make sport-suspension available for the AWD cars and they lifted the AWD cars relative to the RWD cars to make room for the drive shafts in the front of the car. So your 4-series or 3-series AWD version was a little more like a subaru outback, with the wheel-gap and how they fit the AWD in there relative to the ride height. All of those things contributed to it being a real sloppy vehicle as far as handling...and then there was the terrible BMW electronic steering. I also had an older luxury mercedes C class and it too was pretty soft, but it at least was meant to be soft IMO, vs. the BMW sport-line with electronic suspension. BMW is finally offering sport suspension on AWD 3-series chassis now, but it's been years to get to that point. I modded mine with a shock upgrade that made them stiffer, ACS lowering springs specifically tuned to the car and config, and stiffer sways. That made for a pretty good handling package where the shocks were in line with the springs, etc. Then I got a Camaro 1LE, which is just absolute amazingballs as far as handling. While I didn't expect or want a Stinger to feel the same, it's kind of like going back to square one when you drive any other vehicle. You quickly realize how much body-roll there is and how soft they are. To put it simply, the Stinger is pretty soft, it has a good amount of body roll, the stock sways illustrate this pretty clearly. It's not just the OEM all season tires, they are absolutely ridiculously skinny for a car of this weight. I also had a Elantra GT N-line and way lighter, it came with the same width tires as this Stinger. That car was much better "buttoned down" than the Stinger. That's not limited to Kia, BMW did the same thing with skinny tires too (one of the other things I upgraded there too).
But with a few
mods, the sways, the tires, the stinger can be pretty fun and start to handle pretty decent. IMO, this is better bang for the buck than LSD, but to each their own.
And yes, I agree that the lower end models are generally going to be softer, however, I'd rather have a sportier version of this than the gas-hungry 3.3, when I have a 455hp monster in the garage for my fun days. The 2.5 is plenty fun and comfortable for cruising, especially since I'm not lowering it or stiffening the springs.