Overall rating:

If you're expecting nothing more than ostentatious trinkets from the Kahn RS450, prepare to be surprised, because in dialling in the showmanship it dials out surprisingly little refinement. That said, we still wouldn't fancy being at the bottom of a big muddy hill in one.

Key Facts

Pricing: £76,875
Engine: 4.4-litre turbocharged V8 diesel
Transmission: eight-speed automatic, four-wheel drive
Body style: five-door SUV
Rivals: AC Schnitzer BMW X5, TechArt Porsche Cayenne
CO₂ emissions: 253g/km
Combined economy: 30.1mpg
Top speed: 130mph
0-62mph: 7.8 seconds
Power: 313bhp at 4,000rpm
Torque: 516lb.ft at 1,500rpm

In the Metal:

Unlike the majority of tuners prepared to pimp your SUV, Kahn's aim is to make its work look like it came from the original manufacturer, which is to say that it curbs the wilder excesses associated with aftermarket SUV dressers. The RS450 is nonetheless a head turner, edge-bound in bespoke composite plastic like a top-end guitar would be in mother of pearl. It's showy while retaining the original Range Rover's decorum. Yet Westwood would approve: it has 22-inch rims and quad Cosworth branded back pipes.

While Kahn can re-trim the cabin to your moneyed heart's content, the 'standard' RS450 keeps interior appointments to a minimum. You get a Kahn rotary gear selector, a clock circled with Swarovski crystals, a few bits of trim here and there and a custom key fob.

Driving it:

The RS450's giant wheels bring only one question to mind. It's deciphering the answer to that question that dominates the driving experience, belittling everything else on the mental checklist of the average road test: will those ruin the ride?

They don't. Yes, there's an extra patter as the imperfections of the road make their way past supercar-thin rubber, via bass drum sized alloys, through shortened springs and to the seat and wheel, but it doesn't undo the Range Rover's inherent suppleness. In fact, some might actually prefer this setup, because the car rolls less than its relatively stilted progenitor, both when cornering and braking.

Elsewhere there's really not much else to report. You get the same ultra light steering rack, slightly sluggard turn in, illuminating visibility and colossal pickup from the 4.4-litre TDV8 engine. The Cosworth pipes don't really make things sound much fruitier. From the inside, anyway.

What you get for your Money:

The list price of the RS450 is £76,875, which is a good five grand less than a stock Range Rover Autobiography. The Kahn is based on the less well-equipped Range Rover Vogue, but we'd argue that the Vogue has enough toys and that Kahn's work adds to the cachet of the car significantly; love it or hate it, it's an obviously enhanced product.

Kahn claims that £20,000 of work goes into this, but the company actually asks for about £8,000 more than the stock Vogue's list price. For that you get a set of 22-inch wheels, a full body kit including the Cossie back pipes, springs lowered by 25mm, and the aforementioned interior work. Again, this is probably polarising: one man sees a pricey body kit, another a great value customisation.

Worth Noting

The RS450 is an aperitif to the main event, because if dressing up a diesel Range Rover seems a bit all-show-but-average-go, help is around the corner.

It will be called the RS600 and, claims Kahn, it will be the quickest SUV on the planet - quicker, even, than the BMW X5 M and the Porsche Cayenne Turbo. It'll use a Cosworth tuned version of the 5.0-litre engine in the Range Rover Supercharged, pushing out around 600bhp and cracking 0-62mph in four seconds or so.

The engine is currently undergoing type approval, but as soon as it's road-ready, we'll be first behind the wheel.

Summary

If it's possible to straddle ostentatious and restrained, Kahn has done it. The RS450 isn't cheap, but the fact that it's priced low enough to sit below Range Rover's official range topper makes it seem good value to us. The most surprising thing is that it retains the original's ride integrity.