I towed for one year with 08 Nissan V-6 automatic and 18ft Rockwood Mini-Lite. Added Timbren helper springs in rear, and Monroe Sensa-Trac HD shocks, and Blue Ox Sway Pro WDH. On the flat it was ok, but any hills, and +9000ft passes in Colorado, the Nissan just bogged down and screamed in 2nd gear (also added a HD Trans cooler). Stay below 20ft, and you should be ok. AWD also is not great for towing and power. Add 1000lbs to the dry weight, and try to stay below 80% of your TV capacity (Ultra Light wt TT).
Now towing Lance 1685 with HD Ram with 5.7 Hemi and 3.92 gears (also with Blue Ox Sway Pro) and seems to be the perfect combination with no issues.