Dated, the information on the Sumitmo remains current. There may be
other, more modern, low-rolling resistance tires:
One of their biggest advantages is a 51 psi sidewall tire pressure.
This allows me to also exploit tire pressure:
I don't have the reference handy but it turns out that higher pressure
tires are less subject to hydroplaning and stop a little faster. I
know for a fact our two Prius take turns like they are on rails.
I don't know your dealer but in North Alabama the dealer's replacement
tire in the past as been the Sumitomo T4s.
Consumer Reports updates their list from time-to-time. You might
consider getting an online subscription or seeing if you can find
their 'annual' review book at a bookstore.
I order my Sumitmos from Tire Rack and have them shipped to the house.
I then take them to a local Firestone shop to have them mounted,
balanced, and front-end alignment. Both cars have the Firestone life-
time, alignment guarantee.
You might consider mounting a pair of the largest diameter tires that
fit on the front. I had originally installed them to see if I could
tweak a little lower rolling resistance:
I found on our NHW11 front wheels, these larger diameter tires
measurably improved straight-line stability. It 'cured' the neutral
stability and makes long distance driving much nicer. I suspect the
greater moment of inertia is the primary cause but by running smaller
diameter tires in the rear, the caster angle will also be slightly
One other thing, you might consider a four-wheel alignment. This can
normalize wear across the treads and result in longer tire life.