towing with suv???

It depends on the SUV. Diesel is far, far superior to gas with anything other than large truck based SUVs. I towed a Nash 25c with no real issues from seattle to Yellowstone and Glacier with an ML350 diesel v6 (very similar to Jeep Grand Cherokee diesel). Sticker weight was 5750, and we were running around 6600 (ml350 is rated to 7200). Equalizer 4 points hitch. We had no problem pulling or braking (diesel has wonderful engine braking), but there was some mild sway and porpoising when it got really windy. Slowing to 55 for a bit took care of that, but a better hitch, and lower weight would help too. As a rule, I'd look for dry sticker weight about 2k under rated weight, and diesel is highly recommended.