Have a 2007 120 series Prado and tow a 17.56.2 OB. Tows it fine and most of the time you don't really notice it's behind you. Yes you can always do with more power but have not really needed it anyway. Prado now has 215,000k's on it as well and apart from a new set of Injectors at 180,000k that's about all I've had to do to it.
Can comfortably cruise on the limit and above if needed all day. Only mod is had the suspension upgraded mainly for the lift not the van. Got it done prior to buying a van. Normal OME 2" lift with medium springs in the rear. The car sits level when the van is attached.
Have never had a WDH on it and don't think I will ever put one on as it drives extremely well. It's all about making sure your van is loaded correctly. I prefer to have the tanks full as well as it seems to tow even better.
The 120KD motor from 2007 has plenty of power and different to the previous 120KZ. Also having a 6 speed manual instead of 5 speed.
Can sit in 6th most of the time on flat roads and just drop it back to 5th when needed. You will notice the van on big hills but I haven't come across any that stops me. On average I have been getting around 15.5lts / 100 with the van on most trips. Sometimes a bit more if headwinds, windy mountain roads or a lot of hills but averages out to that. Usually 2 kids, 3 adults (grandmother) and 180ltrs of fuel in tanks. Love the fact that i can travel with the van over 1000k's before worrying about fuel stops.
Figures are from mileage and how many ltrs i put in to fill so are actual not estimated.