What's the story?
Citroën's not a name you normally associate with luxury. But when the French carmaker purchased Maserati in 1968, the pieces started to come together for a proper grand tourer. Two years later the SM was born, with a 2.7-litre Italian V6 engine, a top speed of 140mph and a 0-60 time of 8.3 seconds.
Why should I want one?
It might look very '70s now, but the SM was way ahead of its time. It used hydro-pneumatic, self-levelling suspension rather than springs, while the power steering only kicked in when really needed (while parking, for example). The headlights were hooked up to the steering and suspension, so they stayed flat and in line with the wheels at all times. The windscreen wipers even adjusted themselves to cope with how hard it was raining.
What to look for
As long as it's been well cared for during its lifetime, you shouldn't have too much trouble finding a fully functioning SM. However, its technical eccentricities mean that any neglect is likely to result in some pricey TLC being needed. Problems with the oil pump, fuel pipes, timing chain, rusty valve tips, clutch and windscreen surround are common, and can add significantly to the post-purchase cost if you're not careful.