BMW has a huge range of engine options for the 3-Series. The smaller turbo-diesel, the 318d, is the fuel-saving champion, using just 4.5 litres/100km in the official test (city and country combined). But that engine option is only available in the station-wagon body.
The next step up is another turbo-diesel called the 320d, which is just about as frugal and can be had in a sedan. These engines might be the fuel-sippers, but both produce plenty of oomph and feel as though they propel the car effortlessly.
For utter refinement, however, you need to look at one of the petrol engines in the 3-Series line-up. And there is plenty of petrol choice.
It starts with the 316i, which uses a turbocharged 1.6-litre four-cylinder that is smooth and quiet, although straight-line performance is adequate rather than exciting.
From there, you move up to the 320i, with a turbo 2.0-litre which is just as smooth but has more urge.
Then there’s the 328i, which is a hotter version of the turbo 2.0 that, frankly, has more performance than you will ever need. Some people like that.
The 335i is a turbocharged 3.0-litre six-cylinder. It is smoother and even faster than the 328i, and is for people for whom too much is barely enough.
And then there’s the almighty M3, a bona fide supercar with an even more powerful 3.0-litre turbocharged inline six. Unnecessary, but awesome if that’s your thing.
For something different again, there is a hybrid-powered 3-Series called the ActiveHybrid 3, which teams the 3.0-litre six-cylinder engine with an electric motor to boost performance. This is also ridiculously fast. In fact, this hybrid is more about performance than fuel efficiency, so don’t automatically link it with fuel sipping as in, say, a Toyota Prius. The 3-Series diesels use less fuel than the ActiveHybrid 3.
The 3-Series cars are available with a six-speed manual gearbox or the more popular eight-speed conventional automatic. The M3 is the exception here, with a choice of either the same six-speed manual or a seven-speed computer-controlled manual which shifts gears by itself, like an automatic.