Some other observations about this 2.5 sonata:
My uncle complained a lot about slippage and lack of grip on his recent monal trip, there was some rainfall but shouldn't the all season pirellis work better in the rain than summer tires?
I checked the prices in Hyundai dealer for regular service items and they're just insane. Like 4k for just an oil filter. Total oil change cost was coming around 16k. Granted the 2.5 takes 6l oil, should be cheaper for 2.0 sonata and elantra but still a good bit above Toyota and Honda.
I did test the car after clearing the scan code and the acceleration felt amazing. Better than the 2010 2.4 accord this same uncle had before and also better than civic 1.8, Elantra, corolla, etc. Don't know where the complaints about being underpowered are coming from.