Well, I don't think Nissan would allow the 4-banger Xterra on the road if it was so drastically weak that it was dangerous. I'm sure thats why they don't offer the Automatic 4-cylinder.

Isn't there a certain legal requirement for a car to have enough power to survive life on the freeway? If so, does anyone know what the minimum requirements are for HP in cars?

With all the weak hybrids and 3 cylinder Geo Metros out there, it would be cool to see how low auto manufacturers can go with their "budget" cars.