The new Ginetta G40 R is a stripped out road car that packs an impressive punch. Weighing only 800kg and powered by a 2.0-litre engine it'll lap most race tracks faster than any Ferrari. And thanks to Mazda's MX-5 drivetrain, the gearbox is slick and precise. So what's this winning formula like to drive on the open road? Here, Steve Sutcliffe find out.