The introduction of first the S-Type and later the X-Type brought Jaguar within the reach of many buyers who would not otherwise have been anywhere near its customer base. In business terms, these cars can therefore be thought of as a Good Thing, but I often feel that they lack a certain confidence, as if they were not the cars that Jaguar people really want to make.With the XJ saloon range, however, Jaguar is operating right in the middle of its comfort zone, and the car tested here is one of the best examples of that. It's the less expensive of two long-wheelbase models, using the 4.2-litre V8 engine in naturally-aspirated form (the Super V8, which is the extended version of the XJR, uses the same engine with a supercharger and costs about £11,000 more).The extra length amounts to 125mm, or just under five inches, and all of it is supplied to the rear passengers. There is no change to the luggage compartment volume of 470 litres, and from the front seats the car feels just like a regular XJ.Since Jaguar has a tendency to make cars which are very large on the outside and surprisingly small on the inside, this means that drivers who are more than six feet tall might wish for a few extra cubic inches around them, but there are unlikely to be any complaints of that sort from the folk in the rear. There is quite simply a colossal amount of room back there.If you plunge into the options list, you can turn the rear of the LWB into something like a second home. The test car had pretty much everything, including a separate multimedia package for the back seat occupants. There's a DVD player, with 6.5" screens built into each of the front headrests, and with a control unit hidden in the central armrest.Being a conscientious sort of fellow, I had intended to spend the next couple of paragraphs telling you about how I lazed around in the back of the car one afternoon, watching movies and generally having a splendid time. Unfortunately, I first had to find out how to get the control unit started (it has some sort of electronic lock), but the handbook which tells you how to do that wasn't supplied with the car. Shoot. Oh, well. I'm sure it's wonderful.I can confirm, though, that the business trays fitted to the back of the front seats are very nice - as they rather ought to be, since they are a £750 option - and the lamb's wool rugs supplied front and rear for an extra £285 add a considerable touch of class to what is already a very classy car.The extra five inches add 24kg, or about 1.5%, to the kerb weight of the standard XJ8. According to the official Jaguar figures this makes no difference to the acceleration, fuel economy or CO2 emissions, which I find slightly difficult to believe. But there's no doubt that the LWB is very quick, and reasonably economical for what it is - I improved a little on the combined fuel consumption figure, recording about 27mpg despite some occasional rapid motoring.And rapid motoring, I may say, is a lot more fun than you might expect of a luxury saloon. Just before I took delivery of the LWB I spent some time in a Ford Mustang which, like the Jaguar, produces 300bhp. There is not the remotest doubt as to which car can cope more easily. The Mustang fought against its engine's power, while the XJ smoothly and easily transferred it to the road.This wasn't surprising, since the XJR deals with 400bhp just as effectively. But that's not to say that the unsupercharged LWB is underpowered. Once the chassis has settled into a bend, a touch of throttle persuades the back end to contribute just that vital fraction more to the cornering process. This only just noticeable effect quietly makes it clear that the LWB is a supremely well set-up car with a magical balance between power and handling.There's a lot more evidence to support that view. A long-wheelbase car should, all other things being equal, be more stable than a shorter one, but it might also be less effective on turn-in. The XJ8 LWB is indeed very stable, but some fine work on the front suspension and steering (helped, of course, by a great deal of power assistance) means that it also turns in amazingly accurately. A slight movement of the fingers and you're in the corner, without fuss and without effort.Not only does this behaviour make the LWB a far sportier car than it has any right to be; it also removes the last vestige of stress from the driving experience and contributes yet another level of comfort and enjoyment to whoever is lucky enough to be behind the wheel.Anything which costs this much damn well ought to be impressive, of course, but there's more to it than that. You pay for the creature comforts and the unique Jaguar ambience, but you also benefit from the mechanical craftsmanship of people who really know what they are doing when it comes to performance and handling. Thanks to them, the XJ8 LWB is a superb car which achieves the incredible feat of making more than £60,000 look like a bargain. Engine 4196cc, 8 cylinders Power 300bhp Fuel/CO2 26.0mpg / 264g/km Acceleration 0-62mph: 6.6 seconds Top speed 155mph Price £60,370 Details correct at publication date