MERCEDES-BENZ has taken an unprecedented step in the Australian full-size luxury SUV field with its third-generation M-Class by fitting it with a potent four-cylinder turbo-diesel engine.

, , Producing the same power and torque as the larger V6 diesel it replaces, the downsized unit consumes 30 per cent less fuel, contributing to an average 25 per cent improvement in fuel consumption across the range.

, , In addition to all-round improvements, a downsizing in price and upsizing of equipment is aimed at attracting customers considering cars from the next size down as well as higher-priced direct rivals – but is it enough to place the M-Class at the top of luxury SUV shopping lists?