Drivers looking for a mid-size sport utility vehicle (SUV) have three broad options.

Those who regard the car as purely functional and who value reliability will go for a Japanese model, such as the Toyota RAV4 or Honda CRV, which costs $140,000 to $150,000.

Those drawn to prestige will go for the BMW X3 or Mercedes-Benz GLC, which are priced between $210,000 and $260,000.

And then there are those who yearn for exclusivity and are prepared to pay for it. This is the spot the Alpina XD3 fills. It costs $370,800 - a cool $100,000 more than the most expensive BMW X3 on sale.

The engineers at Alpina, a German specialist maker of cars based on BMWs, have taken the chassis of the X3, slotted in a high-performance 3-litre turbodiesel inline-six power plant and peppered the car with Alpina badges.

The X3, on which the XD3 is based, was launched in 2010 and refreshed in 2014. A third-generation model is due later this year.

To get a sense of how rare Alpinas are in Singapore, consider these numbers. According to the Land Transport Authority, there are only 31 Alpinas registered here, of which six are XD3s.

That makes the car rarer than Ferarris and Lamborghinis.

Each Alpina is individually numbered. The test car is the 210th XD3 to roll off the production line at the Alpina plant in Bavaria, Germany.

Looks-wise, there are various bits that set the XD3 apart from the X3. The most obvious is its 20-spoke, 20-inch Alpina rims.

Inside the car, the centre console and instrument cluster are typical BMW fare, along with the classic orange BMW ambient lights. The steering wheel's leather has double stitching in Alpina colours of blue and green.

The Alpina logo, about the size of a one-dollar coin, is glued onto the leather seats and woven into the fabric of the floor mats.

The gem in the car is not these designer bits. It is the engine. The 3-litre diesel cranks out a staggering 700Nm of torque from a low engine speed of 1,500rpm. The instant availability of torque makes the car a hoot to drive - it responds to the slightest prod.

The engine is paired with a ZF- sourced eight-speed gearbox that is also found in many BMWs.

On the move, the car does not propel off the block like a 100m sprinter. Rather, it takes off with the steady, confident stride of a mid-distance runner, with loads of stamina in reserve. The car is most at home on long open roads, which Singapore lacks.

Its muscular engine does not sound like a diesel power plant. It has none of the characteristic clank of diesel engines, even when idling. The only times I found it too loud were during cold starts in the morning.

The car has frills such as a head- up display, headlights that swivel with steering inputs and a panoramic sunroof.

But it is not without its quirks. Instead of gearshift paddles behind the wheel, it has buttons about the size of a 10-cent coin, which take some getting used to. The engine is also relatively thirsty for a diesel car. Over a 48-hour, 240km test drive, I averaged 9.5 litres for every 100km, against the manufacturer's claim of 6.6 litres.

I also found I had to explain to the people I ferried what Alpina is about. The boss of a small and medium-sized enterprise, who has a Lexus LS460 limo and a seven- seater BMW 216d Gran Tourer, asked: "Is this a new brand? People will pay more than $300,000 for this car?"

Overall, the XD3, like all Alpinas, is more illusive than exclusive. For those who want to drive something special and understated, Alpinas fit the bill perfectly.

For most others, Alpinas are just high-performance BMWs with a bigger price tag.

But is the exclusivity worth the price tag? The answer will always be subjective.

But what is plain to see is this: The XD3 will remain a rare car that only a small group of buyers can afford and that only an even smaller pool will actually buy.