THIS diesel-performance lark is starting to get interesting.

Not so long ago critics were dismissing derv-drinking motors as noisy, smelly and slow modes of transport.

How things have changed.

The hot hatch market has received a welcome boost thanks to recent technological advancements, ditto big saloons previously more accustomed to wafting along to the tune of a petrol V8.

And the best bit? Even when you're driving the door handles off your chosen charge, it'll return previously-unheard-of levels of fuel economy.

Granted, 4x4s have also done rather well out of the recent diesel explosion, but there's also a lot to be said for something the size of BMW's 5 Series being capable of delivering sensible economy and enough thrust to make drivers of traditional sports cars nervous.

The BMW example is no accident, by the way, as the German firm is probably the best exponent of the executive diesel.

A case in point is the company's three-litre oil burner - possibly the smoothest and most responsive of all the six-cylinder diesel units out there, and one that works best when mated to a six-speed auto gearbox.

But not even switched-on user-chooser company execs, already familiar with the 5 Series in 530d flavour, could have predicted what BMW engineers had in store for the critically-acclaimed car and engine combo.

Ladies and gentlemen, allow me to introduce BMW's 535d (pictured) - a special car due to the inclusion of two turbochargers, although not in the conventional sense.

Without boring you with all the details, the improvements centre on banishing turbo lag - a bane in any performance driver's life - and upping torque (and overall performance) to supercar levels.

With the blowers linked sequentially, the first turbo ensures low-speed responses are sharp, while the second, larger turbo delivers power in abundance further up the rev range.

The result? No nasty gaps in the engine's pleasingly wide power band, and the impression that the 535d could sprint clear of almost anything bar products from Stuttgart and Modena.

With 413lb/ft torque at 2,000rpm and the ability to sprint to 60mph in 6.3 seconds, the Five's twin turbo motor also outputs a not-inconsiderable 272bhp.

But the torque - or pulling power - figure is what allows you to amble around in a high gear and experience mind-boggling levels of mid-range acceleration.

If you're interested, you'll need to make a choice between the regular SE-spec Five or its evil twin, the M5-alike Sport variant.

The former looks and rides like a normal 5 Series, which means you can stick the car in "drive" and leave it their all day long.

Opt for the badge deletion option and much fun can be had embarrassing drivers of more conventional, petrol-powered performance machinery. Porsche's new 911 produces "only" 295lb/ft of torque, you know...

The real fun, though, comes when opting for a 535d kitted out to BMW's Sport specification. Apparently this option proved especially popular with buyers of the old car, and it's easy to see why.

Visually this car demands a double-take, as you could easily think that you've stumbled across BMW's new uber-saloon, the M5.

The differences are subtle, as the diesel Five comes with more aggressively-styled bumpers, flared side sills, de-chromed window surrounds and some fetching 18-inch double-spoke alloy wheels.

The only thing lacking is the quartet of exhaust pipes that are the trademark of modern "M" motors. The 535d Sport comes with a pair of business-like chrome tailpipes.

A cornerstone of the 5 Series Sport variant range is a suspension set-up that has been heavily influenced by the M5 (read sporting and firm, but not harsh), and a ride height that is a noticeable 15mm lower than the norm.

Inside, you get a pair of supportive sports front seats, a chunky sports steering wheel and racy aluminium trim for the fascia, doors and sill kick plates.

On the go, mid-range thrust is of the jaw-dropping variety. The full effect is achieved by nudging the auto 'box's lever over to the "Sport" setting, and then bracing yourself for impact with the horizon.

And there's none of the usual off-beat diesel soundtrack and whistling turbocharger accompanying your land speed record endeavours - just a cultured growl from the car's engine and twin tailpipes.

It's not all brain-out fun, though, as there's the not-so-small matter of cleanly channelling the engine's prodigious power and torque through the Five's back wheels.

Despite the presence of numerous traction and stability aids, the car commands a serious amount of respect when being driven enthusiastically.

The big BMW's underlying talent and the Sport-spec modifications do a terrific job keeping things under control, but you also have to know what you're doing when you're exploiting a car boasting this level of thrust.

If you're the kind of person who hates waiting lists, the 535d Sport could prove a more rounded purchase than the M5.

There's a lot to be said for owning a car that's been influenced by Formula One technology and is powered by a screaming petrol V10 motor, but the 535d is the car that comes the closest in combining mind-bending performance with real-world running costs.

It's no exaggeration to say that the 535d, especially in Sport trim, is one of only a handful of cars in current circulation that force a rethink of accepted automotive wisdom.

For more information, call Woods BMW on 01256 703703.