For the time being, Litchfield’s power upgrade package for the Toyota GR Yaris consists of little more than a plug-and-play ECU tuning box (£600). It lifts power from 257bhp to 300, with a useful step up in torque as well. The really big power increases will come once the ECU itself has been cracked and new intake and exhaust systems developed. But in a car this size, isn’t 300bhp plenty? After driving Litchfield’s uprated GR Yaris (it has two, in fact), I couldn’t imagine wanting more.