best to join a facebook group,might take some weeding out to ge the right answer.ive got the fist model with the least power  and with a throttle module.

get the best brake controller ,youll be pulling a large vessel behind you.

My boat only weights about 1.5 and tows it very well.

 Although on paper all of those 4cyl or v6's might look to pill that sort of weight, the reality is they can only do it for short distances. The turbo's (and head gaskets) are working their arses off to make the necessary horsepower to pull 3 tonne loads. Also the gearbox oil and gearbox clutch packs burn out pretty quick and stars to shudder like a bastard. 

if towing big weights, there's no replacement for displacement (and for the record I love small turbo high HP engines, they just don't have the torque and bottom end grunt to move the big weights) 

 I've got one and had others for work.

Over 2 tonne can be hard work for them.

If it's just to the boat ramp and back you'll be OK but I would want something bigger.

Unless you want to re-map, upgrade suspension and get 25l/100km.

 I've got a 2013 Colorado and it towed my 2.7 tonne boat no problem to Exmouth and back numerous times.