Welcome to the Prius-v forum. The low ground clearance is CRUCIAL for maintaining good efficiency, especially at highway speeds. The v already has a 6" clearance rating, which I can attest is pretty accurate. (I have dents underneath to prove it)
I will need the ground clearance. I will be in rougher country than I where I currently am, and need a car that can park on curbs and handle the minimal plowing that is likely to be done outside the cities. A small SUV was recommended, but I love my little Prius c and it is new, so I am hesitant to replace it My C Three is less than 5.5" right now, as I did not want the alloy rims that would have put it at 5.5", so kept the smaller steel rims. When it isn't plowed well, I won't be able to go at all, so no efficieny there. I need the ground clearance more than the efficiency at this point. I'll be looking for taller rims (hopefully not alloy) but i don't think that will gain more than an inch.
