He did mention above that... "Plus the Yukon was humming about 2600-2700 RPM with the tow/haul mode on and in the highest gear - it was working hard to pull the heavy boat." So it sounds as though that was with the tow mode on, which would explain for the higher rpm as I'd think most flat towing roads you'd be closer to the 2k rpm range or so. A 2019 GMC Yukon Denali per Google says that it can tow between 8,100 - 8,400 lbs depending on the model, which is going to be about 1k+ lbs greater than the towing capacity of the X5 that the OP has. Which would make for another reason as to why I wouldn't want to tow the boat with the X5. Also, as mentioned in my first post of the thread, per the GW website they tested the boat out and came to the conclusion that it weighed "6040 lb. (including persons, fuel, water, gear, engines & accessories)." I'd subtract around 400 or so lbs for the persons that are included in that weight but then I'd add another 1k+ lbs for the trailer and likely another 500-600+ lbs for a full tank of fuel and any other gear you might be trailering in the boat as well. Which will put it over 7k lbs, maybe even closer to 7,500 lbs.