Mazda 6 TS2

Diesel is by far and away the most popular fuel of choice for luxury cars like BMW’s 7-Series – and the same can be said of family hatchbacks, too.

Mazda is launching a new lightweight, high-efficiency 2.2-litre oil-burner in the 6 next year, and it promises to be one of the best engines the Japanese firm has ever built.

Available in 123bhp, 161bhp and 183bhp forms, the unit replaces the existing 138bhp 2.0-litre. It features a stiffer engine block and a chain-driven balancer shaft to improve refinement.

Sure enough, on the motorway the 183bhp model is a brilliant cruiser. However, it suffers from turbo lag, so low-speed driving round town becomes a series of lunges. Torque steer is a problem under hard acceleration, too.

By contrast, the 161bhp variant is the much better day-to-day option. It has the same fuel economy and CO2 emissions figures of 51.4mpg and 147g/km as the 123bhp unit, but delivers more usable power than the 183bhp motor.

In addition, the TS2 can be specified with 18-inch optional alloys – which barely affect the ride but increase grip – plus a blindspot warning system.