Not sure if it's OK to bump old topics, but here goes.
We towed our 2010 K-Z 16bh some half dozen trips last summer with our 2016 Kia Sorento EX V6. No WD or sway control yet. I know this is not much, but couldn't get out more due to other commitments. No long trips with longest day being 350 km or so in NW Ontario. Obviously no mountains either. 90-100 km/h speeds while towing where comfortable, except one headwind tow where I chose to drop the speed down to 85 km/h to keep the revs down. The trailer tracked quite well even in one very windy day. My wife was comfortable driving as well. We always towed with empty tanks
Based on my experience with our specific set-up, travel and towing habits, Kia Sorento V6 can tow our small trailers on flat land at Canadian highway speeds. I know this is not ideal set-up, but it works for us right now.