Alpina D3 Bi-Turbo: 152mph, 45mpg

Well now, here's something you don't see every day - a tuner putting a smaller engine in a car! It sounds bizarre, but in this case it makes a lot of sense.  Alpina used a 3-series BMW as the basis for the D3 Bi-Turbo, but fitted with a mildly tuned version of the 123d's 2.0L twin-turbo diesel motor, which isn't available from BMW in the 3-series.  This is a majorly high-tech motor, using sequential turbocharging (like BMW's twin-turbo gasoline six as seen in the 135i, 335i, and others) and direct common rail fuel injection to acheive 214bhp and 332lb-ft of torque.

In the 3-series, this equates to a 6.9 second 0-60 time and a top speed of 152 - all while returning a combined 45mpg, or 52.3mpg combined on the EU cycle.  It's a very tempting combination of first-class turbo torque and miserly fuel economy, which BMW doesn't offer - anyone figure out why that is yet?

Of course, the D3 Bi-Turbo is fitted with the typical Alpina goodies - tasteful bodykit, deep-dish Alpina alloy wheels, and custom interior trim.  It's also blessed with a BMW warranty, which isn't something you can say about most tuned cars.

The real appeal to this car will be to people picking a company car in the UK; with a CO2 emission rating of 143g/km, which is quite low, all things considered.  It's a smart market position that Alpina have picked out for the D3.