I tow a 1.4 tonne van with my 101 that made 120HP when new, and I'm sure a few of those ponies have escaped over the years so stop complaining!

But seriously, 700Nm should be heaps for anything short of a truck surely?

My work Hilux (Yes I know but I'm going somewhere with this) makes 130KW and 450Nm and regually tows 2,000Kg - trailer mounted excavators, skid steers, generators, etc.

I can sit on 100 anywhere in top gear towing that sort of stuff, so if you exrapolate that out then 700Nm should tow 3,100Kg with the same ease (give or take - heavier vehicle, aerodynamics of the vehicle and the trailer, etc). I'd leave it standard in that configuration, you'll extend the longevity of the engine and driveline by doing that, unless you plan on upgrading and that isn't so much of a concern.

Just my 2 cents.