THE fastest diesel SUV on earth does not cost the world. , , Well, that’s Audi’s take on the SQ5 TDI – not a numberplate sequence, but the Q5’s intriguing new performance flagship., , Is it true, though?, , While this 250km/h beast blasts to 100km/h from standstill in an unseemly 5.1 seconds – beating the triple-turbo BMW X5/X6 M50d fraternal twins by a few tenths of a second – it is ‘green’ enough at 6.8L/100km to score a tax credit and price cut., , This means that instead of costing more than $100,000, Audi only charges $89,400 before on-road costs. There you go then. Easier on the planet, lighter on your wallet … the SQ5 TDI might be a bit of a motoring miracle., , Unusually for a German performance SUV, there is nothing especially extrovert about the styling – although a subtle body kit, glitzy grille, and oversized wheel and tyre package (20-inch on the standard car, 21-inch as previewed in our $15,000 extra, limited-run test car) do differentiate the newcomer from its more mundane Q5 brethren., , Not surprisingly, the interior is special to behold. , , Superb quality materials, an excellent driving position, tons of room up front (although rear legroom is tighter than the crossover’s length and width suggest), a sizeable cargo area, and a logical – if initially fiddly – dashboard layout, are both long-entrenched Audi hallmarks and industry benchmarks. , , Nevertheless, the posh yet practical SQ5 TDI ups the ante with appropriately grippy sports seats (finished in soft Nappa leather and lovely Alcantara faux leather), high-end audio and satellite navigation, and sufficient levels of aluminium-like trim to give this SUV a sense of sporty occasion., , But none of these quite prepare the uninitiated for the theatre that this 230kW 3.0-litre twin-turbo diesel V6 unleashes., , Armed with a trick exhaust sound actuator – which uses speakers to pipe a rortier (and less diesel-like) noise in and around the vehicle – the SQ5 TDI turns from quiet and refined at idle to a rorty and racy revver as speeds soar, filling the lush cabin with an aural urgency of quite indistinct nature. Is it a V6? A V8? , , The accompanying forward thrust – the speedo’s needle seems to swing around in rapid unison with the tacho – brings to mind some sort of supercharged … V7.

That’s right, folks. The diesel clatter, plus two blowers, plus faux tailpipe symphony give the SQ5 TDI a sound all its own., , Make no mistake the noise carries you along in a trance. This is the type of vehicle where a careful eye on the dial is essential because with a torrent of instant torque available – all 650Nm of it – there’s no real sensation of speed., , Particularly impressive is how smoothly the electronic stability control and Quattro all-wheel-drive system lay down all that torque through a dry, tight corner. , , Packing a slick-shifting and quick-thinking eight-speed auto, even mid-turn the Audi will lunge forward like someone has stabbed it, and doesn’t shudder or shimmy., , But, beyond scalding straight-line performance, there is nothing remotely sporty about the SQ5 TDI’s dynamics., , Tipping the scales at a hefty 1850kg, this is a heavy vehicle with a high centre of gravity, and a chassis that is inclined to stick to the road like gum., , This means that while the steering does an exemplary job of placing the Audi exactly where you need it, there isn’t much feedback if you’re into that sort of thing. , , Consequently, as the brakes ably wash speed away into a downhill corner, for example, there’s no escaping the unnerving feel of shifting mass, which can create a sense of bulk and unwieldiness. , , Even with the three-mode Audi Drive Select system that remaps the suspension and steering set to “Dynamic” – it helps minimise excessive body movement – there is no connection between car and driver. , , Oh, hang on, you say. This is an SUV, so we ought to give it some slack, right? Perhaps. But this is no miracle sports car. Some expectations management might be required. , , What else? On the optional 21-inch wheels – standard fare is 20-inch rims – ride quality ranges from busy to choppy on anything but glass-smooth surfaces. Unfortunately the standard wheel set-up was not available for us to sample, so we can’t comment on it. We do recommend a try-before-you-buy. , , Finally, in a related qualm, a fair amount of road noise permeates the lovely interior, although to be fair the Audi is no worse than most German SUVs., , So there are a few downsides to driving the fastest production SUV diesel in the world., , However, the upsides are performance bragging rights (for now), exquisite quality, iconic design, reassuring safety, and real everyday useability., , There’s also no denying the twin virtues of relatively good value and potential low fuel use – merits that benefit your pocket as well as the planet. , , Potent and pious, thy name is SQ5 TDI.