BMW X5

Dropping any pretensions at being a mud-plugger whatsoever, the ultimate X5 is all about image. We doubt you'll ever see one with dirt on its spoilers, but thanks to a whopping 347bhp 4.6-litre V8, most other cars won't see you for dust. A 0-60mph sprint time of 6.5 seconds is plainly ridiculous for a car of this bulk, and it won't stop pushing the air aside until it's reached a phenomenal 149mph.

It nearly has the handling to match the performance, too. Unlike the fast but crude Mercedes ML55 AMG, the BMW behaves pretty much like a car. It's extremely responsive with barely a trace of body roll, and also offers huge grip - no surprise considering those vast tyres and the 4x4 transmission.

There is a downside to that bad-boy wide rubber, though, and it's the ride. Most of the time it's firm without being too unpleasant, but hit a pothole or cat's eye and you will be rewarded with an almighty jarring thump.

There's another shock in store, too. BMW has priced the iS at ί¿½54,000; that's a massive ί¿½10,000 more than the standard V8 X5, and ί¿½2,000 more than the awesome M5 saloon. But if you have your heart set on a fast off-roader, we'd at least wait to see what the Porsche Cayenne has to offer - if the rumours leaking out are true, its performance and handling will make even the ultimate X5 seem weedy. had Mazda not got hold of the name first this would be called the MX5. The X5is is the ultimate vehicle for those who feel they need to be seated up high while going quickly. But most buyers will realise there's little point in having a large 4x4 with no off-road ability when a BMW M5 is more capable and cheaper.

At a glance

* High-performance version of X5 is on sale now, priced at ί¿½54,000

* Uprated 347bhp unit: 0-60mph in 6.5 seconds and on to 149mph