What is it?
This is Audi's range-topping Q7 V12 TDI, driven in the UK for the first time.
Powered by a mammoth 6.0-litre V12 diesel engine, producing 493bhp and a truly colossal 737lb ft of torque, the V12 is the Q7 for those who struggle with the concept of self-constraint and have very deep pockets.
At just shy of six figures, the 12-cylinder Q7 is nearly twice the price of any other model.
What's it like?
A guilty pleasure. Even the most humble of Q7s is a pretty conspicuous way to travel, but with 20in wheels, daylight running lights, V12 badges, wheel arch extensions and a chrome plated grille, this particular Q7 is about as conspicuous as it gets.
And yet I have to admit that on the road, the big Q7 is remarkably satisfying. Far from being a party piece powerplant shoehorned into an unlikely bodyshell, the V12 TDI is impressively well resolved; not only does it start and rev smoothly, but it also does so with a not-unpleasant voice.
Moreover, the Q7 is happy trundling along at slow speeds without feeling like it's being constrainted. And then when you do want to add a little speed, the throttle progression is such that you can do so accurately.
Which is a good job, because if you summon the V12's full muster the Q7 accelerates at a pace not far off that of a BMW M5. It'll race to 62mph in 5.5sec, an odd experience in something that weighs 2635kg.
Wisely, Audi has tuned the suspension and braking to cope with the extra performance. With the adjustable air suspension set to dynamic, the V12 Q7 rides lower and more stiffly than any of its siblings, and that helps to control (if not entirely hide) the masses involved.
The brakes are now carbon-ceramic, measuring 420mm at the front and 370mm at the rear. But try to rely on the Q7 too heavily and its limitations are easily exposed; it's better to knock the suspension back to comfort - where it copes rather well with our pitted roads - and be more measured with the power.
Should I buy one?
So expensive is the V12 Q7 there really is only one reason you would - because you can. However monster the performance, it canít justify the additional £44k over the already very competent and brisk 4.2 TDI.
And you wouldn't choose it for its efficiency; 25mpg isn't exactly a disaster, given its pace, but it isn't going to offset the purchase cost.
Finally, if you want the absolute star of quick SUVs then the (cheaper) Porsche Cayenne Turbo is more accomplished. Still, however irrational it may be, the Q7 V12 does hold appeal - for its technical achievements, if nothing else.