Poke the starter button and the big V8 under the bonnet rumbles into life with a potent thrum, which can be turned up to a throatier warble if you switch the drive mode selector to Dynamic and activate the sports exhaust.
Once you’ve nudged the stubby gear selector into drive and buried your foot to the floor, the engine’s mighty forward thrust is akin to surfing a tsunami wave. There’s certainly the out-and-out pace to see off the diesel BMW X5 M50d, although the petrol-powered Porsche Cayenne Turbo is even quicker.
The only problem with getting all that power onto the road, though, is Audi’s eight-speed automatic gearbox. There’s a noticeable lag when you put your foot down; those 429 horses are held back before they can really get going. This is most noticeable at low speeds, such as when joining a roundabout. Thankfully, putting the gearbox into its Sports setting speeds things up a bit, and using the steering wheel-mounted paddles to manually change gear masks the gearbox's dithery nature almost entirely.
There’s no denying the SQ7 is a huge car, and you certainly sense its heft when you steer left then right through an S-bend, but the way it handles and grips the road is deeply impressive for such a practical seven-seater. Just bear in mind that smaller Sports SUVs such as the Porsche Cayenne feel even more agile and involving.
Vorsprung trim also comes with four-wheel steering; this turns the rear wheels in the same direction to the front ones at speed, boosting the SQ7’s stability on faster roads. At slow speeds, though, the rear wheels turn in the opposite direction, helping the big car turn in to tighter corners with the enthusiastic character of a hot hatchback. The steering itself is nicely weighted to give you confidence in what the front wheels are up to, although you get more feedback in a Cayenne.
All SQ7s come on adaptive sports air suspension with a selection of driving modes to soften or stiffen the set-up. When you pop the suspension into its softest Comfort setting, ride quality is as good as it gets in a super-fast SUV. Yes, the regular Q7 is even more supple, but the SQ7 still breezes over all manner of lumps and bumps, thanks to its standard air suspension. Even the Vorsprung model, which rolls on whopping 22in alloy wheels as standard, is remarkably comfortable, although it does pick up on surface imperfections a little more.
Sit at a steady 70mph and there is a little more roar from the fat tyres than you’d hear in a standard Q7, but the car suppresses tyre and wind noise incredibly well – better than the X5 M50d and Cayenne. Even with that V8 rumble, the hefty diesel engine is nicely refined around town, and only starts sounding strained when accelerating hard right at the top of the rev range.