2006 BMW Alpina B5

Compared with the rev-hungry, stiffly sprung M5, the B5 delivers a much more relaxed approach to life in the (very) fast lane. Alpina’s ethos states that the enjoyment of a car is less about absolute power and more to do with the manner in which that performance is delivered. In the B5's case it unfolds in the blink of an eye, with 62mph arriving in just 4.6 seconds – BMW claimed 4.7 for the M5.

And this is a genuine automatic too – the B5 doesn’t expect you to be fiddling with gear sticks or paddles as you waft across entire continents. The ZF six-speed autobox even dispenses with first gear under normal circumstances, and pulls away in second just to keep everything smooth and silky.

Contemporary road tests pointed out that there was no whistle from the Nautilus-type compressor, despite it spinning at 105,000rpm at a crank speed of 6000rpm, nor was there a Jaguar-esque whine from the belt-driven epicyclic gear-set that multiplies the drive to this mini turbine. They also talked of seemless power delivery throughout the rev-range and were amazed that the B5 was utterly docile at low revs, too. Makes you wonder why BMW didn’t develop this for itself.

Fuel economy, not something possibly at the forefront of ones mind when considering a 500bhp super saloon, is very respectable too, considering the grunt on hand, with The B5 managing mid 20s to the gallon easily enough, thanks partly to the highly efficient Valvetronic technology that limits valve lift during cruising, and the miserly power consumption of the supercharger - just 20bhp at full boost compared with 100bhp for the Jaguar XJR's Rootes-type blower.

The current enthusiast owner says; ‘Describing the car I can use cliches like the best car I’ve ever owned – and that is quite accurate. It combines amazing performance with outstanding levels of comfort.

‘It is very pleasant to drive, exhilarating when you want it to be, blisteringly quick and can scare the living daylights out of you at how quickly it reacts. And whilst it can move quickly it gives you a degree of luxury that few other manufacturers can touch.

‘Although a direct competitor to the M5 it is much easier to drive smoothly, more economical and lastly there aren’t many of them about, which in itself makes it a touch unusual. Overall it was great fun!’

This is a far more subtle looking machine than the M5 of the period. There are pinstripe graphics that run around the front splitter's edge and along the flanks of the car, a subtle boot spoiler, plus Alpina badged BMW wheels and a boot badge – and that’s about all there is to distinguish the exterior from a cooking 545i.

The gunmetal paintwork is in generally excellent order, save for a small mark on the offside rear wheel arch. The wheels themselves were refurbished in 2016, and still retain a virtually unmarked appearance.

There’s a full toolkit in the boot, which looks unused. It contains no spare wheel, as is the way of BMWs from this period, but there’s a pump for tyres and a can of get-you-home tyre inflator. Standard model 5 Series cars had run-flat tyres, whereas the Alpina had Michelin Pilot Sport 2s – Alpina not being a big fan of the run-flat idea.

We couldn’t see any stone chips on the nose and overall the car looks laser straight. And the noise from the V8 as it climbs through the rev range is addictive. Just hold on.

This is no stripped down racer, rather it’s a luxury saloon with a seriously potent powerplant. Inside the black leather seats, each sporting an Alpina badge on the backrest, are in beautiful condition.

There’s a an embossed metal badge on each floor mat, lest you forget the car's pedigree, and the steering wheel is re-upholstered in special ultra-soft leather. It also and gains two discreet nipples behind the horizontal spokes that are the manual controls for the Switch-tronic gearbox.

Alpina logoed blue dials and various high-gloss wood veneer inserts complete the interior makeover. It's a very subtle interior as well as being a superbly comfortable one. It even has a sunroof and heated seats – what would M5 owners think? (Who cares?)

Alpina re-engineered the BMW DSC traction control system to allow a degree of wheel slip so that enthusiastic drivers could steer with the throttle without turning the system off. If it senses a sudden loss of grip it cuts engine power, but if it decides you’re just exploring the limits of adhesion, it lets you have your fun.

Under the bonnet the big V8 hides under an Alpina badged plastic cover, and is crossed by an induction tract that snakes across to the supercharger from the air cleaner.

The under bonnet area isn’t quite as clean as the car’s exterior but it’s no big deal, and as it’s a 2005 BMW you’re unlikely to be looking under here very often anyway.

If you do you might notice surface corrosion on the Alpina supercharger’s casing, but again, it’s purely cosmetic. In fact a weekend with some detailing products would see this are looking fantastic.

The huge brakes are from the South African spec BMW 760i, plenty big enough to rein in the much smaller 5 Series, despite all that power. Under the car we spotted nothing untoward, with just mild surface corrosion on some of the alloy and steel parts.

There’s a full BMW/BMW specialist service history with this car. There is also the original Alpina handbook, Alpina inspection certificate from January this year (plus several historic ones too), and a stack of receipts for servicing and maintenance work over the years.

These are accompanied by a pile of old MoT test certificates which corroborate the mileage, as does the included RAC vehicle history check. The car also comes with two sets of keys.

Alpina only sold 80 of these sublime mile, munching super saloons in the UK, plus four Touring versions. As a result they don’t come up for sale very often. This one is in superb condition with a solid history, and represents a rare opportunity for an enthusiast to acquire a car whose value will only go one way.

Our estimate for this car Is £13,000 - £18,000.

Viewing is always encouraged, and this particular car is located with us at The Market HQ near Abingdon; we are open weekdays 9am-5pm, to arrange an appointment please use the Contact Seller button at the top of the listing. Feel free to ask any questions or make observations in the comments section below, or try our ‘Frequently Asked Questions’.