Don't judge A8 on the quantity of cars sold; judge it on the quality of people who buy them, says the Audi spokesman, rattling off the names of a few high-profile car nuts who have one.

Now that its flagship has a long wheelbase option and a total of six engines, the company expects to sell 1,500 A8s in the UK in a full year, compared with the 750 targeted at launch last spring.

With the introduction of the bulbous-nosed W12 quattro and 3.0-litre diesel and petrol engines, the range now runs from £46,175 to £75,775.

Although Audi retailers are pretty good at selling optional extras, a LWB 6.0 has the potential to be a £115,000 purchase fully loaded, despite the already extensive standard equipment list. That's in S-class and 600 limousine territory and, be assured, in terms of technology, comfort, ride and equipment the A8 can compete. It's even reasonably close to the competition in residual value. CAP takes a dim view of the limo market and predicts 34% after three years/30,000 miles (Mercedes S600L 34%, BMW 750iL 37%).

The A8 is an exceptionally well-made car, with features unique to the luxury D sector, among them the aluminium space-frame bodyshell that makes it 41% lighter than steel rivals, and permanent four-wheel drive. In almost all engine formats, it's a fantastic car to drive. The 3.0-litre V6 petrol feels a little underpowered, but the 3.0-litre TDI V8 available only in SWB has everything going for it. Not surprisingly, Audi expects that diesel will account for 50% of A8 volume by next year.

The long wheelbase adds just 8kg to the GVWs of the rest of the range, so the differences in performance compared with the standard models is not noticeable. Rear passengers get about 10cm extra.

The range-topper is astonishingly agile, very quick and reasonably economical. Audi, feeling bullish with an all-time record 14,000 sales in March, believes this is the car that will draw the luxury market into its showrooms.

Strengths: Build quality, styling, performance, comfort
Weakness: Brand doesn't yet fit into the luxury sector.
Opportunity: Chance to raise profile through chauffeur market
Threat: There are more than adequate smaller engines
USP: Lightest, fastest, best equipped
Price: £75,775
Engine: 6.0-litre W12 450bhp petrol
Transmission: 6sp Tiptronic, 4wd
Performance: 0-62mph 5.2s, top speed 155mph
Efficiency: 20.5mpg comb, 331g/km CO2
Servicing: 9-19,000 miles/2 yrs
CAP RV (3yr/30k): £25,400 (34%)
Rivals: Mercedes S 600, BMW 760Li, VW Phaeton W12 (Gervais Seymour. May 11 2004)