It has always been the case that whatever Mercedes you buy, from the cheapest saloon to the most expensive limousine, the impression is that the company started with a solid block of steel and chiselled away at it to make a Merc. The so-called "sports" SL models are no exception when it comes to solidity and build quality. People like that in a car; it makes them feel safe, that they are getting engineering value for money, and that it will never let them down. In used-car terms the SL is nothing less than a blue-chip investment. From the pounds 80,000 stratosphere down to the pounds 5,000 slum, there is an SL for just about everyone.
Although the sedate and comfy Mercedes SLs have always been successful on the US west coast and in the nouveaux riches English home counties, the models have a proud sporting lineage. This goes back to the track, when the legendary 300SL was created to compete in the 1952 racing season. Adding gull-wing doors to a production 300SL contributed to the myth, although the roots of this model, and a much less potent 190SL open-topped roadster, were a saloon car. These models were replaced by the cleanly styled and quintessentially Sixties SLs which were becoming less sporting and more sybaritic. These cars featured a removable "pagoda-style" steel hardtop, which transformed the convertible into a snug winter coupe.
Just in case you wondered, SL stands for sehr leicht, but the 1972 model was far from "very light" - it had clearly been on a high-calorie binge. Nevertheless, this model, which survived until 1989, has been the most successful and recognisable SL of all. Its successor SL took the hi-tech route and returned to original SL principles - and proved that Mercedes should still be taken seriously as producers of high-performance sports cars.
While the early SLs are collectors' items and the Sixties versions are contemporary classics, it is the last two versions which are the most "affordable" and practical buys. To find out what the appeal of these cars is, I went to see Richard Leach, proprietor of Richards, a Surrey- based Mercedes specialist. "Quite simply these are unique sports cars. Nothing else is built like them: properly serviced and maintained, an SL is a sports car for life. The quality of the mechanicals, upholstery, bodywork and switchgear is second to none. The SLs' unique selling point, though, is the removable hardtop. Pop that on in winter and it turns a convertible into a proper coupe. You cannot possibly tell that the car is meant to be convertible; the transformation is incredible."
Remarkably, Richard Leach has witnessed a huge resurgence of interest in the older model from the Seventies. "When the new SL came out, prices of the old car dropped significantly, but recently the values have been climbing. Basically there is nothing like it on the market, and technically it is much simpler to look after."
A glance at the range produced between 1971 and 1989 is very confusing. There were six-cylinder models, the 280 and 300SL, which some drivers find too sedate. Then there were the V8s - the larger the number, the bigger the engine. All are thirsty for fuel, but many believe that the 500 and 560SL were the finest luxury sports cars ever built.
When you are buying, a service history is essential - even a Mercedes can deteriorate. SLs don't normally rust, but on a very old example, corrosion can nibble at the wheel arches, the sills and around the headlamps. Underneath, the chassis can also rot. Mechanically, the engines should last a lifetime, but if little used or neglected they will corrode internally. Be warned: if the engine sounds noisy, or is sluggish and leaks oil, there will be big repair bills. Prices for these models in first-class condition are going to be pounds 12,000 to pounds 14,000. And a good car, especially a late Eighties example, can go for more than pounds 20,000.
Richards had a 1984 280SL in red with beige cloth, alloy wheels, a rear seat and ABS brakes for pounds 14,995. Twelve years old maybe, but it looked brand new. Over at Sunningdale Motors in Berkshire, a top-of-the-range late-model 1988 500SL tipped the scales at pounds 21,950. Clearly, these old cars won't go out of fashion.
If you want a really cheap SL, then the fixed-roof coupes, badged SLCs, which are longer, heavier and much less desirable, offer a cheap entry into the marque. However, the pounds 4,995 SLC I spotted on a south London car lot looked decidedly tatty up close. In such a situation it is best to walk away.
At the other end of the scale are the new model SLs. Sophisticated, hi- tech, very safe, very fast and remarkably accomplished cars. Ask Diana, Princess of Wales. This car is the aristocrat of sports cars and virtually faultless in use.
An SL that is not perfect, or has an imperfect history, is almost unsaleable. Always buy from a dealer or specialist, or get a proper engineer's report before taking the plunge into SL ownership. Choose between a range-topping 600SL, or the equally competent but cheaper 300SL. Somewhere in the middle is the multi-valve 300SL-24. These are all automatics, but what a choice. Obviously, the best ones can be found at Mercedes dealers. Derwent in Leeds had a 1993 600SL with just 10,000 miles on the clock, and every conceivable extra, retailing for pounds 68,995. Whereas a car trader operating from a very large house in Buckinghamshire offered me a 1989 500SL which was equally over-equipped, for just pounds 34,999.
Looking at used SLs is instructive - almost without exception they look as good as the day they were delivered. Clearly, the SL is a very special kind of sports car. One day maybe all convertibles will be this good.
Richards 01483 272020; Sunningdale Motors: 01344 20072; Derwent 0113244 3000.