So the manual for my '05 OR 4x4 says it can be flat towed provided I don't go faster than 60 MPH and that I stop towing, start the Xterra up, and idle the engine every 500 miles.

My question is what if I go faster than 60 mph? What happens? Globalthermonuclear war or nothing? I am guessing it is just some conservative limit that isn't tied to anything besides lawyerly fear - but those are famous last words.