The BMW M5 is the best argument I can think of for not buying a new car. When the hottest version of the lauded 5-series was launched in early 1999 it cost a hefty £60,000. Today the same car with 50,000 miles on the clock is changing hands for less than £25,000 and prices are falling. But don’t get me wrong, the M5 is one of the greatest sports saloons you can buy, I just think that at less than half-price it is even better.

Powered by a 400bhp 5 litre V8, the latest M5 — E39 — is the most powerful M-series ever. Performance is impressive: 0 to 62mph in 5.3sec and a top speed limited to 155mph. Best of all, the V8 has huge torque, making gear changes almost unnecessary: you can go from 20 to 100mph in fourth.

On the road the car has limpet-like grip from wide tyres on 18in alloy wheels. But just in case you should get carried away the automatic stability system and traction control (ASC+T) adjust engine power and braking to rein things in when they detect the onset of a slide. For real fun, though, turn them off and enjoy the full 400 horsepower experience.

Another button worth pressing is labelled “sport”. It quickens throttle response, sharpens the steering and firms up the adaptive suspension so that the car feels more alert and closer in character to the smaller M3.

Build quality is to BMW’s typically high standards so be fussy and check that all the electrics work, especially those that adjust and heat the front sports seats. Some cars have a luxury pack that introduces fluted leather upholstery and walnut trim.

While the M5 is strong, abuse and neglect can prove costly and all servicing should have been done by a BMW dealer. Service intervals are variable and dependent on use and driving style: relatively stress-free motorway cruising will extend the intervals but short journeys and hard charging can shorten them to every 6,000 miles. The dashboard indicator notifies the driver when services are due, but beware, these can be reset by the unscrupulous, so insist on seeing the original service invoices as well as the stamps in the book.

The list of standard equipment is extensive and includes leather seats, air-conditioning, an on-board computer and six air bags. The most popular option was the £4,000 communications pack that comprises a television, satellite navigation and a telephone. On used cars the telephone adds little to their value but expect to pay up to £1,500 more for examples with the full communications pack.

Buying from a franchised dealer will be more expensive but also more reassuring. However, if you decide to deal privately have an HPI check run on the car, it costs about the same as a tank of fuel but could save you a lot of heartache. Such is the M5’s performance and desirability that it’s no surprise insurers put it in group 20.

Face-lifted in June 2000, later cars are easily identified by the circular sidelights surrounding the headlamps. They also gained three-position memories for the electric front seats, a six-CD audio system and park distance control. BMW slashed the price, too, making the updated cars £8,000 cheaper than when this M5 model was introduced.

USED BUY: BMW M5: CHECK IT OUT
Comfort Steering column electrically adjustable
Exhausts Four tailpipes hint at car's blistering performance
Brakes Check for vibration and pulling to one side
Audio CD player optional before June 2000
Insurance Group 20; get a quote first
Spare wheel There isn't one, just a tyre repair kit
Electronics TV and satellite navigation add £1,500 to used-car value
Gearbox Six-speed manual only
Servicing Between 6,000 and 10,000 miles, dependent on driving style
Clutch Check carefully for slip or judder
Cabin Luxury pack includes fluted leather and walnut trim
Seats Full electric adjustment up front includes lumbar support; seat warmers standard
Lights 2000 face-lift introduced soft-glow circular sidelights
Wheels 18in alloys and tyres expensive to replace

VITAL STATISTICS
Model BMW M5
Engine V8, 4941cc
Power 400bhp @ 6600rpm
Transmission Six-speed manual
Fuel 20.3mpg (combined)
Acceleration 0 to 62mph: 5.3sec
Top speed 155mph

THE ONE TO BUY ...
BMW M5, 1999 T-reg with 60,000 miles. Pay £26,000 at a dealership or £22,500 to a private seller