I bought a 2.0 SE TDi last week, but not towed with it yet, we are off to France next week, so will let you know when we get back (in August)
I've only done 600 miles solo (at an average of 42mpg), so it's a bit soon to say how it goes.
I had a Mk 5 Golf 2.0 TDi before, and that towed our 470/2 Dart like a rocket. The Tiguan is lower geared than the Golf at 30mph/1000rpm in 6th, whereas the Golf was 35mph/1000rpm so that should be better for towing, not sure about the 'electronic' handbrake though.
I've noticed that the factory fitted towbar is 19" (48cm) from the ground to the top of the ball