Like the Range Rover before it, the SD1 - short for Specialist Division number One, the first product from the recently amalgamated Rover and Triumph marques - was a brilliant piece of design. Long and elegant, with styling unashamedly cribbed from the Ferrari Daytona, it was also extremely quick thanks to an improved version of Rover's famous V8 engine. Despite a simple beam rear axle, it handled well, too: well enough for it to become Touring Car Champion in the Eighties. The bad news was that the car just wasn't built properly, despite having a brand-new £27 million factory all to itself. Paint rapidly fell off bodyshells in large patches, giving the car a bad reputation for rust; water leaks through the front and rear screens were common and the Rove's interior was made from previously untried materials that couldn't last the distance. However, Rover struggled valiantly to address the problems and the car continued to evolve into four - and six-cylinder, and even turbo diesel, versions. Build quality gradually improved, too, particularly when Rover switched production from Solihull to Cowley in late 1981. Because the later cars are better made and still very cheap to buy, most people prefer them.

Far and away the most sought-after SD1 is the high-performance Vitesse. Rover was going to call it the Rapide, but Aston Martin Lagonda held the rights to that name and wouldn't play ball, so Rover dusted down the famous Triumph moniker. Seriously large front and rear spoilers were giveaway recognition points, and early cars were emblazoned with a rather tasteless Vitesse decal down the flanks (this was the Eighties, remember), but this was soon made a 'delete option'. Sadly, although the Vitesse did well on the race tracks, reliability was frequently absent on the road. The Lucas fuel injection tended to go off-colour far too easily, leading to mediocre performance and some disappointed owners. I know: I was one of them. During the early Nineties I ran a Vitesse as a magazine staff car and suffered just about every problem in the book. When it was good, it was very, very good; when it was bad it was expensive.

In its twilight months, the Vitesse was tweaked a little further to keep the racing versions competitive, by modifying the plenum chamber of the fuel injection system to a twin-throttle design. The last SD1 off the line was a twin-plenum Vitesse in Silver Leaf paint, which is now part of the Heritage Collection; it's also the second car featured here. A brace of V8s. These two cars really are the first and last of their breed, for the white car is chassis number 33, a pilot-production car built six months before the official launch. I bought it through the owners' club mag last year and have used it daily ever since. For an SD1 it's been remarkably reliable, probably because it was hand-built (by Roberts rather than robots) in the first place.

The lift-up door handles still break fingernails, just as they did those of Motor's test-car keeper in 1976, and once inside you're back to the Seventies with a vengeance. The modular instrument pod was very fashionable, and so were the pale orange carpets that set off the gloomy acres of chocolate velour and black vinyl.
Fire up the trusty all-alloy V8 (the 29th block built, for all you fellow anoraks out there) and you could forgive the car anything. It sounds even better from the outside: a deep, melodious rumble that hints at what's to come. Power-assisted steering, automatic transmission and 155bhp guarantee an effortless drive.
Kickdown has never worked in my time with the car, but the design of the transmission gate, which allows you to shift straight from Drive into second and vice versa, with detents either side to stop you inadvertently hitting neutral or first, makes manual gearchanging a pleasure. It's sheer joy to flick the lever back and feel the extra surge of power as the 'box drops down.

Go into a corner too fast and you'll probably get round, thanks to decent grip and predictable handling. Understeer is the norm, unless the road surface is wet or greasy, when the car's length causes its tail to behave like the pendulum of a grandfather clock. Most of the time this happens so slowly that it's hard to resist the temptation every time you find a deserted roundabout. Where the SD1 shows its age is in a degree of body roll (I tend to brace myself against the handbrake on right-hand bends and jam a knee against the arm-rest on left-handers) and a ride that is distinctly knobbly at low speeds. Hit a bump mid-corner and the beam rear axle will jump sideways, too. But you learn to adjust to these foibles, and I've even become used to the infamous squared-off steering wheel, which contemporary road testers universally condemned.

This so-called Quartic wheel lasted right to the end of Rover SD1 production, but it's less acceptable in the Vitesse. The Vitesse is one of those cars that really benefits from a small, circular Momo-type steering wheel to maximise precision: the steering weights up just the right amount, too. Combined with the slick, five-speed manual gearbox and light pedal pressures, the whole package makes the car feel a fraction of its true size, and it's easy to forget you're in a large executive express rather than a nip-and-tuck GTi. Grip - in the dry at least - is even better than the standard car's, thanks to meaty 205-section rubber wrapped around pretty, lattice-alloy rims, and body roll is tamed by the stiffened suspension. The trade-off comes in a harder ride, of course, but at least it gives an impression of solidity lacking in the earlier car, which feels jiggly rather than supple. In one respect the cars are very alike: they both have long-travel, rather spongy brake pedals, which is an SD1 characteristic.

Fuel injection makes the Vitesse engine notably more responsive than the earlier car's, and it sounds different too, with a higher-pitched hum that gradually hardens as the revs pile up. In the early 3500, the engine never becomes harsh but you're aware that it's working hard once the needle climbs beyond 4,000rpm; in the Vitesse, it simply zings towards its red-line. Thankfully, the Lucas componentry seems in fine fettle and this particular car has the scorching mid-range ability that buyers craved but didn't always receive. Personally, I'd never run a Vitesse as a daily car again; the potential for grief is just too great. But it's often the flawed cars that are the most characterful - and one thing the SD1 is not short of is character.

Mark Dixon