Volkswagen has launched its Polo GTI. We take a look at the powerful subcompact on the road and on the racetrack in Valencia.The fourth-generation Polo GTI makes the sprint to 100 kilometers per hour in just 6.7 seconds. Bucking the downsizing trend, its 1.8 liter TSI engine clocks in at 141 kilowatts - 9 kilowatts more powerful than its predecessor. The added kick makes itself felt on the racetrack. We put a 7-speed dual-clutch DSG through its paces.