I am not a lawyer but worked on a dealer for some time (IT department)
The thing is that any mod (I know people will debate this but it is the truth) voids warranty. With the exception of changing oil and filter yourself, if you change any Hyundai part and something happens to the car later, the dealer can potentially refuse to repair under warranty. The reason behind this is not only what the manual and Hyundai says, but because when the car was designed and left factory, it was tested using OEM parts. The car, as a whole, was tested and calibrated using original parts. Any modification will change that, for good or better, and dealers won't have enough information to troubleshoot the problem properly or fast enough.
You can ask the dealer and they can say "it is fine" now. But it something went terrible wrong and was NOT DUE your mods but will cost thousand of dollars to repair, be sure they won't honor their word, trust me on that! They will say they do not remember or this time, your mod broke or affected something; they are not your friend, they exist to do business. Yes, you can argue with them and debate the whole day but at the end, they have the power to say no and you will have to pay no matter what.