A barely disguised race car for the street, the Subaru WRX STi is the distillation of a theme started by the company with the launch of the original WRX in 1994. The STi version arrived in 1999 and is a now a permanent fixture as top model in the Impreza line-up. The latest rework aims at notching-up the devastatingly fast sedan’s handling via a reworked suspension, plus the electronic trickery of a variable-split centre differential that apportions power between front and rear axles according to need. This is a potent brute of a car that makes the regular WRX seem almost bland.