I have a 2015 Kia Optima EX 118500 miles and has not had one not problem, fingers crossed! I’ve only had to have tires replaced twice, alignment, battery replaced, regular oil changes, and Air filter and cabin air filter. I’ve been hearing about a lot of engine fires and failures but I’ve not even had a issue even similar to those not even a check engine light. I don’t even have any GDI carbon build up related issues. Only thing is I’ve noticed is that the engine is loud at idle with the ticking noise (which is normal for the Hyundai/Kia GDI Theta II engine) I’ve had KSDS ECU update done but that’s it. Idles pretty smooth and rides pretty much like new. MPG is averaged at 33. At my next oil change (120k) I’ll be air filter changed again. I’ll have my spark plugs and major tune up at 150k.