The only underwater hotel in Europe was built in Sweden. The Swedes like to do things differently. This historically applied to their cars as well as their holiday accommodation. However, the Swedish car makers are no longer independent. Volvo Cars is Ford owned and Saab is very much part of the General Motors family. So is the Saab 9-5 Aero tested here just another GM offering?

The 9-5 certainly has Saab DNA in its appearance. The nose (incorporating superb Xenon headlights) is distinctively smooth, shaped no doubt for aerodynamics as much as to retain the Saab face. The stance of the 9-5, and the Aero version in particular, is low and subtly sporting. The sharp five-spoke alloys add to the impression. Saab sensibly resists body addenda on its cars, instead relying on the purity of line in its crisp designs. Parked next to the average modern hatch (such as a Ford Focus), the 9-5 is remarkably low, sitting well below the roofline of the Ford. The Saab is not particularly wide though, ensuring it looks in proportion.

Sit into the 9-5 and you are in no doubt you are sitting in a Saab. The seats are exceedingly comfortable and adjustable. The dashboard is a large flat shape, which may look odd to a non-Saab owner to begin with. Labelling of the switchgear is a little different, and some of it is located where you may not expect. The ignition lock is placed between the front seats, which I grew to really like, though its rubberised surround is prone to scratching. I didn't like the touch screen stereo system. It works in a similar way to that in the Jaguar S-type, but is less intuitive and the graphics could have been created on a Sinclair Spectrum in 1983. The stereo itself has a wonderfully clear sound delivery.

The 'Saab-ness' of the dash is more evident when you get underway. Small 'joysticks' control the air outlets: simply point it where you want the air directed. You may have noticed the "Night Panel" button in the photographs. I don't believe that any other car maker has adopted this simple, but useful function. The idea, derived from fighter jets, is not to overload the driver with stimuli while concentrating on driving at night. Pressing the button blacks out all instruments except for the speedo face. Even that is only illuminated as far as 90mph. I did wonder if the remainder of the dial lights up if that speed is exceeded, but my sensibilities prevented that particular avenue of research...

Not that we didn't drive the car! The version tested here is after all the top-of-the-range Aero saloon, and with prices starting at £27,400 (on-the-road in the UK), counts such cars as the new BMW 525i and new A6 saloon 2.4-litre S-line as rivals, as well as models from the Mercedes E-class range. Saying that, for the money, there are no obvious rivals with performance matching the Aero. The 9-5 is also a little smaller than most medium-sized executive cars, but certainly larger than the BMW 3-series class, so perhaps it can be classed as a medium sports saloon. Sadly, our test car was fitted with the 5-speed auto, indicating its place in life as a motorway cruiser rather than a Nord Schleife bruiser. There was hope though in the form of a pair of tactile paddles on the steering wheel, linked to the gearbox when in manual mode.

Alas, use of the manual mode proved to be a source of frustration for us. On a twisty road, where a downchange was requested to add some engine braking, the electronics more often than not decided to change the gear back up a cog straightaway, meaning that the wrong ratio was selected for powering out of the corner. We soon gave up on this. Hoping that the 'Sport' button would perhaps liven things up was met with disappointment too. The gearbox refuses to hold onto a low gear while braking or cornering. However, in the same mode, you only need to glance at the throttle pedal before the 'box drops two gears in its attempt to move you forward rapidly. In a car such as the Aero, with a torquey turbocharged engine, there is rarely a need to drop down two gears. The sport mode is simply not well matched to the engine. After all that the standard automatic setting proved to be the best option. Changes are slick, and putting your foot down is greeted by a brief downchange, which gives the turbo a fraction of a second to spool up before you are launched at the horizon.

Hard acceleration has always been a big part of the Saab turbo ethos, especially in-gear acceleration, with the 9-5 Aero historically outgunning many sportscars with much higher price tags. This Aero is no different, even with the automatic 'box. The 2.3-litre HOT (High Output Turbo) engine produces a healthy 250bhp at 5300rpm and 258lb.ft of torque. What is more impressive is that the peak torque figure is available all the way from 1900 to 4000rpm. In the manual version, there is an overboost function, releasing up to 273lb.ft for overtaking etc. Impressive numbers are one thing, but the sensation of defying physics is another as you incredulously watch the speedo wind around at the same rate as the rev counter. The visceral force is most astonishing at motorway speeds, where three figure speeds are quickly obtainable, along with double figure points on your licence no doubt!

On the main road at high speed, the Saab 9-5 feels comfortable and composed. It is also notably stable under heavy braking. Take the car away from the safe confines of Armco barriers and service stations though and the 'sports saloon' tag begins to look a little misplaced. For starters, two or three big stops have the brakes waving a white flag as they grumble and fade. There is plenty of room in the standard 17-inch wheels for larger discs. The damping fell short of our expectations too, with a series of low frequency undulations causing the front end to hit its bump stops at speed. The stiffly sprung Honda S2000 sailed down the same piece of road, and the BMW M3 we tested managed it at a much higher speed without any discomfort.

The business of going around a corner isn't all bad. There is lots of grip, as there should be from the Pirelli P-zero Rossa tyres, and communication through the large steering wheel is acceptable given the level of torque the front wheels have to deal with. However, we only managed to find understeer when exploring the chassis' limits. Mild understeer is quite comforting at high speed and when you need to back off mid-corner, but a more neutral stance would be preferable in a sports saloon. The only way to adjust the car we found was to be aggressive with steering inputs, but this is not a safe nor fun way to drive a large car, and is out of keeping with the rapid, but refined nature of the Saab. Perhaps the manual 'box would help, but we got the feeling that Saab drivers are not expected to seek the limits of adhesion, instead relying on grip and go to make swift progress.

With the automatic gearbox fitted, the 9-5 Aero is a comfortable and sporty car, suitable for high-speed cruising, packing devastating overtaking ability. It is a quirky car, but in a likeable way: very Swedish. Thankfully they still make them this way. Like the submerged hotel, perhaps the Saab 9-5 Aero is not for everyone.