Just from my own experience, of fitting towbars for 3years, your GTR would be unable to tow another vehicle on a trailer. Torque and power do come into it, but only in a minor way. The structural strength of the rear of the car plays the biggest part in this decision. In towing, there are 2 weights to take into consideration... Ball weight and towing weight. Towing weight, everyone would be familiar with, it's the actual weight of the entire load being towed... in this cae, a car, and a car trailer - don't forget the weight of the trailer. Ball weight on the other hand is often over looked... it is the weight directly down on the tow ball. This figure can actually restrict some vehicles from even carrying a loaded bike rack.
Skylines, R32 and onwards, were not designed for towing... which is obviously why brands such as Hayman Reece don't make kits to suit, if you were to get one fitted, it would be custom made. Despite being all wheel drive, having good low down torque, great handling, and everything else that everyone has said... the rear end of the car and chassis was not designed to have an extra couple of tonne being pulled along behind it, or another couple of hundred kilos straight down on the rear.
Nissan Patrols and Land Cruisers can tow around 3500kgs with the heavy duty towbar kits... you could buy one of these and tow a GTR and your Datto!