In theory, raising your car on what’s effectively a reinforced balloon sounds like the kind of idea that will take off. The kit is much lighter to carry in your boot than the other set-ups here. It’s inflated by the exhaust, and Draper claims the engine only needs to be idling for the balloon to be filled with air. But it actually required nearly 2,000rpm, and this meant we had to blip the throttle, so the nozzle blew off the tailpipe three times. Also, it won’t fit all exhausts –  the BMW 3-Series diesel is just one omission.