Mercedes-Benz has a reputation for building some of the finest convertible cars in the world, and the new SL is no exception. In fact, only one thing stops me rushing out and buying one: the price. At more than £56,000 for the new SL350 and nudging £70,000 for the SL500, it will break all but the chubbiest of piggy banks.

But there is an alternative: buy the previous model, launched in 1989. You can pick one up for Ford Fiesta money and even the last of the breed represents a hefty £25,000 saving.

Whatever your budget, this generation of SL is beautifully made, and 150,000-mile examples should have a fresh cabin and seats that still support. But beware of cars with the smaller engines, lowly specification and garish colours.

Powered by a range of engines from 2.8 to 6 litres, the pick of the bunch is the 5 litre V8. With more than 300bhp, it propels the car to a top speed of 155mph and cracks 60mph in just over 6 seconds — enough to upset most Porsche Boxster drivers.

But the SL isn’t all about speed: with soft suspension and automatic transmission, the car is more Grand Tourer than sports car. Travel at high speed, roof down, wind deflector up, and you’ll appreciate just how civilised it is. On a crisp autumn day when blue skies tempt you but the thermometer dissuades you, the SL is one of the few convertibles you can drive without fear of frostbite.

Interior space is excellent, the large supportive seats — electrically operated on all models — are supremely comfortable, and the reasonably capacious boot handles soft bags easily, although the wind deflector takes space when stowed.

Revolutionary in 1989, the electric soft top is still a good car-park gag. Triple-lined and with a glass rear screen, it is good enough to handle the worst of the British weather all year round. All cars came with a separate aluminium hard top as standard; most owners fit these in winter, but it’s a two-man job.

It’s important to check both hard top and soft top carefully, particularly the seals. If the hard top is absent the car is probably an import, and you can expect to pay several thousand pounds if you want to replace it.

During the model’s 13-year life it underwent continual enhancement, the most significant improvement being in 1998 when the four-speed auto was replaced with a five-speed auto and ESP (electronic stability programme), and rear child seats became standard. Some owners change badges, lenses and wheels to make the car look newer than it is, so always establish the car’s original build date before buying.

Despite its luxury-car credentials, running an SL shouldn’t be too expensive. Cars at the cheaper end suffer virtually no depreciation and specialist insurers can save you money. Servicing on older cars can be entrusted to non-franchise Mercedes specialists without hurting the resale values.

At 3,900lb, the SL is no lightweight, but drive it gently and you can nurse 25mpg from the six-cylinder, 18-20mpg from the V8 and around 12mpg from the most powerful AMG and V12 versions.

CHECK IT OUT: USED CAR: Mercedes SL500
Hard top A stand is available to store the roof when not in use
CD player Boot-mounted CD standard on all cars after June 1998
Keys Check the car has a full set as they are expensive and difficult to replace
Xenon headlamps Standard on SL500 models after June 1998
Servicing Despite bulletproof build quality cars must be serviced on time
Rear child seat More cosmetic than practical, standard fit after June 1998
Soft top Folding it when wet can mark it and cause stains
Panoramic glass sunroof An option on later cars, nice to have but don't pay a premium for it
Exhaust Rear exhaust box is prone to rust
Insurance Group 20 on all models so shop around for the best quote
Seats Electrically adjustable but very useful memory function is an option on most models
Alloy wheels AMG wheels may look great but are easy to kerb and expensive to replace
Colours SL values are colour sensitive: pay less for white cars and cars with blue or brown interiors

VITAL STATISTICS
Model Mercedes Benz SL500
Engine V8, 4973cc
Power 320bhp
Transmission Five-speed automatic
Fuel 23.7mpg (combined)
Acceleration 0 to 60mph: 6.5sec
Top speed 155mph

THE ONE TO BUY
Mercedes Benz SL500, 1998 S-reg with 40,000 miles and full Mercedes service history. Pay £26,000 at a dealer or £23,500 from a private seller

FOR FOR SIMILAR MONEY...
1998 R-reg Jaguar XK8 convertible
1995 N-reg Porsche 911 Carrera convertible
2000 V-reg BMW M3 Evo convertible
1992 J-reg Ferrari Mondial convertible 3.4t
1989 G-reg Bentley Continental convertible

VALUES: Mercedes-Benz SL500
Mileage 30,000
1998 S Trade £23,150. Retail £27,250
1999 V Trade £25,200. Retail £29,250
2000 X Trade £28,250. Retail £32,250

Mileage 40,000
1998 S Trade £22,100. Retail £26,000
1999 V Trade £24,000. Retail £28,000
2000 X Trade £26,850. Retail £30,750

Mileage 60,000
1998 S Trade £20,000. Retail £24,000
1999 V Trade £21,650. Retail £25,750
2000 X Trade £24,150. Retail £28,250

SL600 £7,500 more than equivalent SL500. SL320 £2,000 less than equivalent SL500.
Source: estimates based on confidential CAP black book prices. 'Trade' is what a dealer would pay to buy your car; 'retail' is what you would pay a dealer