If you want to make the car credibly great, know what's good about it and let it change more than one character in the story. Let it change how they think of themselves, their relationships or their destiny. But don't just name-drop: one reader's drooling fantasy is another reader's clunker.
Strictly speaking, a British
vintage car would have been made between the end of WWI and and the end of 1930. Cars made at that time didn't have the luxuries we now see as standard. Heavy-bodied with stiff suspension, no climate control, no safety features and engines you often had to crank by hand. There were touring cars and luxury cars and the beginning of racing cars, but none of them could match anything made from around 1950, except in terms of style.
A vintage car driver will almost always be considered quirky. A lovingly-restored vintage car is normally only driven on weekends and at club rallies because damage and wear normally has to be repaired by hand, and because they're very dangerous in wet weather.
Perhaps what you want is a
classic car -- anything made from about 1925 through about 1959 (or 1979 if you want to include 'modern classics'). Stimulated by a growing racing-car industry post WWII, many sports cars were produced. However, even sports cars of 20 years ago find it hard to keep up with modern design and construction -- lighter materials, more efficient engines, better brakes and suspension mean that classic and modern classic sports cars are admired more for their history and style than for the reason they were originally bought -- their performance.
British automotive design has tended to be quaint and quirky (like the three- wheeled
Morgan F4) or boxy and dependable (like the
Morris Minor 1000). But in certain periods, some British marques were a watchword for cool. The 1965 XKE Jaguar Roadster is an example: sporty, phallic, elegant, aggressive and jet-set ultra-cool.
An enthusiast would love its styling along with its acceleration, its light, neutral steering (making cornering a delight), and its ability to accelerate
hard into corners. Every classic car needs its quirks and with the XKE it was very high oil consumption; constant replacement of spark-plugs (little disposable devices that light the fuel in the engine); and weak, squinty little headlights that made cornering on bendy roads at night potentially lethal.
Cars change peoples' lives because of the way they come to covet them. To many, a car means power, freedom, control, identity and status. A classic car means a classic image and with the XKE it's all about virility. This is a car you'd drive to have sex with the road, a purring phallic monster that leaves others looking limp and impotent at the traffic lights like a stick of celery in a sauna. This is not a vehicle you take your Mum to the shops in. You'd take your boss's wife out in it for a drive to the country club, intent on a dangerous liaison. Those are the memories that would shape the person who would love a car like this, and that would ring echoes in anyone who'd envy you. The conversations of pea-green jealousy wouldn't be just about the car itself, but what you'd done with it, and who you'd done it to.
Hope that helps.
Being a 47 year old car, I have to say it doesn't purr!!!! 
