Thought I might share my experience as I often see questions about towing with the X-trail/Koleos twins. I used to tow my 830kg tare Jayco Finch Outback with my 2006 X Trail manual petrol (the 132 kw version) - several trips Canberra to Brisbane, NSW South Coast etc. It sufficed, but dropped a lot at the rear and as a result, was light on for traction at the front, especially when starting off on even slight inclines. There are rear suspension mods that might help that situation. When towing I always kept it in "auto" 4wd mode, and kept it out 5th gear to protect the gearbox. Power wise it felt Ok with the FInch, but definitely not effortless. I used to get about 15-16 l per 100klms towing on the highway at 90-100klm/hr.
It was rated at 2000kg and 200 kg ball weight, which seemed optimistic from my experience. By comparison, my current diesel Land Rover Freelander 2 SE TD4 (2.2 turbo diesel 6 sp auto, 118 kw and 400nm torque) is rated at 2000kg with 150kg ball weight. It is considerably more expensive so not really a fair comparison. It barely drops at all at the rear with the Finch attached, feels glued to the ground in any towing conditions, and is hugely powerful in comparison to the X Trail - it will easily accelerate up hill from 100klm/hr when towing and overtaking. Bear in mind that the auto X trail/Koleos diesel tow rating is 1350kg.