As I understand the law, Hyundai (or any OEM) can only deny warranty coverage if they can prove that the modification you did caused a defect in the vehicle. The burden of proof is on them. If you think the tune will still allow the vehicle to run problem-free, then you have nothing to worry about. If you're worried that the tune might cause the vehicle to start acting up, then you can probably forget about the powertrain warranty (at least).
Are these DCT designed to handle that much more hp/ torque in the long run? I could easily a Dealer deny DCT warranty service and probably other drivetrain components if they knew you were using this type of tuning device.