Six inches may not seem like much at times, but that’s the difference between the Toyota Prius “Liftback” and the new Prius V, which is six inches longer, three inches taller and an inch wider. It doesn’t look that much different, but the V becomes a viable family vehicle and not just a novelty of miserly mileage. V is for “versatile,” and this roomy little wagon has flip-fold-stash-expand capacity.