Silvio Calabi: Meet Infiniti’s demon truck, the FX50S

These days you can walk into a showroom and buy street-legal, from-the-factory cars with 500, 600, 700 and even (if you’re filthy rich enough) 1,200 horsepower. So a mere 390 under the hood doesn’t sound like so much any more. But it really is quite a lot — especially if it’s metered out by a quick throttle pedal and fed through a transmission programmed to respond not soon but right now.