IF you didn't think the chunky Porsche Cayenne already looked big or imposing enough, the latest one has an answer.

While actually stretching a tape measure precisely as far as before, the styling has been changed to make this imposing SUV look wider still.

And an 'enhanced power dome' on the bonnet will give drivers in the cars ahead even more visual stimulus to get out of your way.

This added styling toughness (only roof and doors are unchanged from the previous Cayenne) are part of a thorough reworking of the model that single handedly turned round the fortunes of the brand.

It's hard to recall the critical vitriol poured over the first Cayenne when a shocked world of car enthusiasts saw the first one in 2002; many regarded the foray into SUVs as nothing short of a betrayal of the firm's sporting roots.

But the planners were right; the world was waiting for a fast, big Porsche ready for the rough stuff.

Succeeding versions of the Cayenne have both proved increasingly good to drive and looked a bit less butch; even the 'added wideness' of this latest third model doesn't grate in an age where there are lots of really big 4x4s lined up outside the school gates by mid-afternoon.

The Cayenne has been the best selling Porsche worldwide (and in the UK) for years and the current comprehensive update won't harm prospects of that continuing - although its slightly smaller new Macan stablemate might give it a run for its money (sold out for more than a year).

Beneath the new panels, every engine in the Cayenne range has been reworked for more power and economy.

Most radical is the Cayenne S (£60,218), which has shed two cylinders - it's now a V6 - but increased power, and the £61,474 Cayenne S E-Hybrid, which mixes petrol and electric power to give up to 22 miles on current alone and 151mph top speed with both power sources flat out.

The new range starts at £49,576 for the slow selling entry level petrol version and tops out, for the moment, at £118,455 with the 173mph Turbo S.

Most popular model in the UK is the Cayenne Diesel which comes in at just under £50,000 until you're tempted by an options list that cheekily includes heated front seats (£295) and a digital radio (£324) that ought to be standard.

As well as injecting a bit more verve into the range, the Porsche engineers have been through the suspension and tweaked it with the twin aims of adding sporting precision and comfort at the same time.

A morning hooning around the track at the Porsche Experience Centre beside the grand prix tarmac at Silverstone showed that the two-tonne Cayenne gets as close to defying physics as anything made by man.

Less expensive Cayennes (a relative term) rely on good old fashioned steel springs but still manage to corner without drama at unlikely speeds. The Turbo comes with air suspension (a £2,379 option on all other models) that can be made firmer for those enthusiastic cross country drives when you're feeling a bit Jenson.

The air springs also let you pump up the ride height for extreme off-road work, useful on the Cayennes at Silverstone on a course no owner would contemplate at the wheel of a car you really wouldn't to scratch. It will stay halted without a foot on the brake on slopes you couldn't walk up - then head uphill backwards with a dab of throttle. Most impressive.

Out on the road - the real world where most Cayennes will spend their working lives - the diesel impressed with a plush and inviting interior (laden with buttons, though) and was quite quick enough, thank you. It also showed 42mpg at the end of a brisk drive.

So big on the outside but a bit of a miser under the bonnet.