Car Review Audi A4 S4

"Now," says the serene Audi chassis engineer sitting alongside me in the S4, pressing a button on the dash, "you shall understeer."

Through the rain, we pile into a tight left-hander on the drenched Mallorcan race circuit. Sure enough, the S4's nose pushes wide, resisting any effort to be wrestled into oversteer. Sensible. Locked down. Audi-ish.

"See?" continues the engineer in impassive Teutonic monotone. He presses the button a couple more times. "Now you shall oversteer."

We hit a similarly tight-radius right-hander, and the S4 launches sideways into a lurid, tail-happy drift. A fraction before we reach that critical backwards-into-barrier moment, the rear end catches, and the S4 barrels out on to the straight. Most un-Audi.

It's quite a party trick, and one that rapidly dispels TG's biggest criticism of the old S4: that it simply wasn't engaging enough to justify the premium over a top-spec diesel A4.

But this is the all-new S4, and that magical button is controlling Audi's new 'drive select' system which adjusts the steering, dampers and, most importantly, the quattro's new 'sport differential'. Similar to the torque vectoring on the BMW X6, it varies the amount of torque distributed to each driven wheel. Audi calls it 'inverse ESP' - instead of braking a spinning wheel, the diff pumps more power to the wheel that can use it best.

In 'Comfort' mode, it's set to safety-first understeer, but in 'Dynamic' mode - and in the right road conditions - it'll let you get quite spectacularly crossed up before deciding to put a halt to all the fun.

It's a similarly bipolar story with the engine: Audi has ditched its tried-and-tested V8 in favour of an all-new supercharged 3.0-litre V6. Power is fractionally down on the old S4 - 328bhp plays 339bhp - but torque is up by 22lb ft to a mighty respectable 324lb ft. That's good news for acceleration - the S4's 0-62mph time is down to 5.1 seconds, a full half-second quicker than the previous generation - and even better news for economy, up to 29.1mpg from 21.2mpg. That's nigh-on BMW M3 pace with 40 per cent more economy, and vital ammunition against those who feel it might not be in the best taste to launch a big new petrol supersaloon into the current climate.

Sadly, the new V6 just isn't as visceral as an M3's V8 - or, for that matter, the V8 it replaces. Despite a pleasingly off-beat thrum at idle, the engine is subtle and muted at any revs, the supercharger whine registering as little more than a whispering hiss.

That's in keeping with the performance, though. There's a silky smooth delivery of power throughout the rev range - no hammer-blow of torque, but instead a flat, urgent, linear wave of acceleration. It's the sort of engine that lulls you unwarily into triple figures rather than scares the bejesus out of you.