These problems were with the older stingers, 2018 and 2019. I think Kia have sorted these out with the 2020. Someone will correct me if i am wrong, but I believe they have been sorted out.The test drive(s) will reveal all. You will fall in love with the performance. Listen for any extraneous noises from hatch lid or sunroof (other sources are much less common; and most Stingers don't make unasked for noises). Brakes could be a pulsating annoyance; aftermarket pads take care of that if it happens (hasn't to me). Check the paint very carefully. Some vehicles have flaws beneath the forward corner of the headlight assemblies (if so, usually just the driver's side for some reason); chipped rear edge of hood; forward edge of hatch lid; and any pinpricks in the clear coat, or chips where road damage would not have caused them, are indicators of a rare paint adhesion issue: they get mentioned on here noticeably, but most cars are fine. Just be careful.
Same for me as far as the test drive goes. As someone that never really considered Kia, driving this car really changed my perspective and I fell in love with the Stinger.The test drive really sealed the deal for me. I knew about this car and it’s power but wanted to step away from Kia bc of the car I had before it (2018 optima) that I hated with a passion. Once I actually drove it, I had fallen in love regardless of any issues. It was also the gts that I had driven which made it even better but the AWD GT1 was my choice and haven’t had any regrets since.