The 540i is the most powerful 5 Series Touring you can buy. It is brilliant, delivering scintillating pace that gets you to 62mph in just 5.2sec and you get four-wheel drive (xDrive) as standard. It sounds sweet and, like all 5 Series', comes with a slick eight-speed automatic. If only the fuel economy was better it would be perfect – officially it averages 35mpg but you might struggle to achieve that in the real world.