I just got my 04 yesterday and drove it from Seaside, CA to San Jose and back to Monterey - about 160 miles. Straight from the dealer, the tires are at 41 front and rear. Mostly freeway driving, but some 2-lane as well and a minor amount of local streets. Speed kept varying bt/wn 55 & 65 on the highway. No stability problems, no pull, no trouble lights - just a real strong rubbery/plastic new car smell on the interior. Temp ~ 60F. Got 54 mpg right out of the box. Dropping a bit now that I'm making shorter trips to under 50. I can't see that less than a 5# change will make a practical difference in either mileage or wear - both are far more dependent on driving habits ... jack rabbit starts ... coasting before braking ... lateral g's while turning, etc., in addition to terrain.
Finally...someone showing in city better than highway...I was getting concerned...since this was the primary reason I have placed an order for a Prius...great IN CITY gas mileage...my drive to work is very similar in distance, speed and traffic lights...Thanks so much for your information. Mike
Perhaps because Toyota's priorities are not the same as the priorities of all their customers. Why does Toyota have the Prius run the ICE when it's not needed except to keep the catalytic converter warm? Because their top priority is keeping emissions low, not fuel economy. But if I could flip a switch, I'd add the extra 0.01% to my emissions and get back the 0.1 mpg I'm losing.