Have SS wagon and was advised by dealer that transmission oil cooler is standard fitment. Towed 2000kg boat from near Newcastle to Melbourne back in August without problem using Holden (Hayman-Reece) 2100 kg hitch with load equaliser. Guess you would only need 1600 kg hitch but if load heavy on hitch suggest equaliser, looks odd but works OK.
Fuel economy was about 15.3 l/100 km heading up with empty (700 kg) tandem trailer and about 22l/100 km coming back. Kept things moving both ways 90-100km/hr up and 90-95 km/hr back and was big boat with a lot of windage. Probably the first time I have filled a car up three times in one day.
Trailer had override brakes which was probably (in hindsight) not correct in at least one state (should have been electric) but had no problems. Goes without saying to check car and trailer brakes and carry spare tyre.
Take note of the manual which says to leave the transmission in sportshift when towing.
Good luck, they make an excellent tow vehicle.
