Well... Haven't had one myself, but did peruse a couple whilst looking for mine - very tidy indeed those late T4s (all the toys and that bigger engine..)
(...reason we didn't take one of them in the end were due to some accident damage on one - a tree fell on the roof and the repair had been botched! The salesman from the other seemed a bit of a crook!)...
The standard 2.5tdi in mine already surprises me (cruising at ease at 120kmph and often find myself pushing 130-135 without realising!) and has more grunt than my car! - so can only imagine how the 150 will turn the km's/miles!
If you can lay your hands on one, very tidy motors and will do you proud - can't imagine they'll be cheap though...
Nice example of one here (though in Germany), but with a price tag to match!
http://suchen.mobile.de/fahrzeuge/d...200&makeModelVariant1.modelId=33&pageNumber=2
Or this very tidy Exclusive in the Netherlands:
http://www.marktplaats.nl/a/caravan...51fa109c354bbabe740c1b&previousPage=lr&pos=13
Not many around for the moment though, they're the only few I can find with this quick look...
Of course if you're prepared to make the effort, then Germany/Netherlands are the place to go to fetch one (and for the time being until Brexit kicks in, less paperwork!)
In actual fact we almost went for an early T5, but in the end the T4 won hands down - solid and bags more character...
Good luck!