If the OEM thermostat is 212 degrees, and the listed ones are 190 and 192, I'm not sure how that is an exact replacement. I suppose using 85 octane in a ZR1 Corvette is "acceptable" also, but it doesn't mean there won't be a sacrifice of some sort (performance, knock).
I'll agree OEM would be best.
I reached out to two local dealers and both confirmed there is no recall for my vehicle regarding coolant temperature or thermostat issues. There is an "ECM update" for misfiring/knock though, which is interesting considering I don't have a Theta II. I was advised to wait for a colder day to more easily duplicate the issue. If they can't definitively prove an issue, they can't be reimbursed by Hyundai for warranty parts and labor. So to allow things to go smoother, "help us help you" and wait for a cold day. I'll report back once I have an update. Thanks everyone for your input (yes, even Imp4. I wasn't trying to sound condescending or combative, and I appreciate your input).
There is a TSB on the heater issue. Hopefully they witness it malfunctioning so they can fix it for you. The engine misfire ECM update is different than the Theta II debacle. The 2017-2019 Elantras have had a history of random misfires and coil pack issues so it’s a valid ECM update.