Okay, so how long before the fuel savings pay for the added hardware? It's not that clear because e-4WD is only used on a few specialized vehicles like Nissan's March (see video below the fold). Estimating exactly how much a hybrid improves fuel efficiency is not a trivial task but as more vehicles use e-4WD, it should become clearer. Also, the system's primary goal is not improving efficiency but horsepower (Torque: 109 pound-feet, Horsepower: 90 hp). Performance ... hybrids? "That's an oxymoron" you might say, laughing, before you remember what Lexus is up to.
While the idea is rejected by most automakers Nissan is planning to make performance hybrids. Greens like the growl of a good engine and watching a guy get smoked in a race, even if the EPA thinks it's a contradiction. Soon, when talking about a hybrid, you won't just ask how much more fuel efficient is it but how much more POWER does it offer. The lack of a battery in the e-4WD should keep the costs low as well.