Strangely, if the starting point is one of an identity no more distinctive than a black hole, the task becomes easier. Take the case of the Nissan Primera. No-one can picture what it looks like, beyond sensing that recent examples look similar to the first ones though there was a complete model change along the way. Play it safe, keep it familiar, because we're too cash-strapped to take any risks: that was the idea. It was the inward- looking philosophy of a manufacturer in trouble.
Now, if an up-front revamp makes people notice the Nissan for the first time, they won't be comparing old with new. You can see the result of this thinking. A big, bold face with a topological distortion of the usual Nissan "winged" air-intakes, giant headlights with polycarbonate lenses, assertiveness all around: it's all very millennial.
Those headlights bring Nissan into the modern technological world. I was at Nissan's European Technology Centre in Cranfield, Bedfordshire, in 1996 for a preview of the then-new, second-generation Primera. Many car-makers had started to use shatterproof polycarbonate headlights, so I was surprised Nissan had kept with glass. "The technology isn't ready yet," I was told, although this was clearly not the case. Anyway, Nissan hascaught up; as well as polycarbonate lenses, the top Plus models have the xenon gas-discharge bulbs beloved of upmarket German car makers.
This nose is the focus of the new Nissan. Apart from the nose, the smoother bumpers and the tapering rubbing strake along the flanks, all designed to make the car appear lower and more dynamic, little else looks to have changed. But looks deceive. This is much more than a cosmetic makeover. The Primera has always been fun to drive, thanks to precise steering, strong roadholding, crisp responses and fluid, interactive handling. "It's a driver's car. So drive it," ran an old ad; occasionally it appeared in magazines with a fold-out page which, if creatively folded back in, caused the giant lettering to read "Sod it". We won't expand on that.
Trouble is, the driver's car was noisy at speed, and its interior had as much charisma as a builder's yard full of breeze blocks. There was nothing to entice you to buy a Primera instead of one of its sleeker, smoother, more refined, more alluring rivals, so people didn't. Might they now? The shapes of the interior's components are little altered, but the colours and textures are more pleasing and the switchgear is tidier. Top versions get a six-disc CD player of terrific sound quality. The driver's seat is still hard, with either a lump or a hollow at the base of the backrest, depending on adjustment. The new range offers two extra variations on the driving experience, in a 1.8-litre engine to bridge the chasm between the 1.6 and 2.0-litre units, and - for the 2.0 only - a Hypertronic continuously-variable automatic transmission. There's a sporty sub-variant of this called Hypertronic CVT M-6, which allows you manually to select from six pre-set virtual gear ratios, and I have been driving a Primera 2.0 Sport Plus so fitted.
That CD player isn't wasted, because the new Nissan is dramatically quieter at speed. The main sound comes from the Sport's wide, low-profile tyres, which make up for this failing by making the most of the Nissan's excellent handling, and soaking up bumps better than you might expect. The engine does make itself heard if you demand maximum acceleration, as the CVT lets the engine speed to its maximum-power point and stay there.
It's better, perhaps, to select one of the manual ratios, keep the revs down and let the engine's ample mid-speed musclepower do the work. The manual override is good for fast, twisty roads, too, avoiding the response delay you would suffer as the CVT finds its optimum setting. Otherwise, the manual shift is largely redundant because the CVT is so smooth and painless. Why have a dog and bark yourself?
From obscurity, Nissan's Primera has finally found a presence. You could never call it beautiful. But it's now worth looking at.
Model: Nissan Primera 2.0 Sport+ CVT M-6
Price: pounds 19,200.
Engine: 1998cc, four cylinders, 16 valves, produces 140bhp at 5,800rpm.
Transmission: CVT automatic gearbox, front-wheel drive
Performance: 126mph, 0-60 in 11.2sec, 28-33mpg
Ford Mondeo 2.0 Ghia: pounds 19,000. Ageing but capable and fun to drive, if less roomy than some rivals.
Honda Accord 2.0i ES: pounds 20,100. British-built like the Nissan, the Accord has superb handling but is expensive.
Peugeot 406 2.0 GLX: pounds 17,485. Revamp rivals prestige German makes for quality. Real value, too.
Vauxhall Vectra 2.0 SRi 140: pounds 17,400. Also recently revitalised, the Vectra is more fun to drive but still stodgier than rivals.
Volkswagen Passat 1.8T Sport: pounds 19,510. Passat still defines the class quality standard. Turbo makes up for engine-size deficit.