The turbo isn't the problem. In Australia XTs are rated to tow 1,800 kg, about 4,000 lb. I believe it is even higher in Europe. So the turbo (and CVT) don't seem to be the limiting factor.I bemoaned feeling limited by the 1500 pound rating on my '16 ForesterXt, and he said the problem is the turbo!
Apparently, the issue is the U.S. uses more conservative criterion for calculating tow limits, probably because of higher speed limits.
I do a lot of towing and decided the 2.5 NA was the better tow option as the turbo would be on boost most of the time greatly reducing mpg.