I can't imagine an SUV transmission would be any sportier than the Stinger's. Is the other project the Sonata N that was recently announced? Because I wouldn't think parts for a cheaper FWD Sonata would be desirable in the Stinger either. I'm not seeing anything that implies Kia would have access to a more appealing transmission/suspension/engine tune that they could simply drop into a low-production trim of the Stinger.
The next N vehicle is a Tucson and they are currently working on a performance DCT that will go in the Veloster N and any future N vehicles to open the market more for them. That tells you their current DCT wouldn't hold up. Also that is NOT a Sonata N, it is a Sonata N-Line which is what Hyundai is transitioning all of their Sport Model trims to. So instead of Sport it would be N-Line. Also it makes zero sense for them to make a Sonata N anytime soon.