Tony,

It's getting cold here in the North (CT). No fair living in Fla! (but I bet the AC takes down your MPG in the summer).

I went for the Michelin MXV4+ (88H) tires for my 2004 Prius at 45,000 miles. They actually improved the MPG somewhat, but were twice the price of your new tires. Another interesting choice for you would be the Nokian summer tires, but they are also a little pricey. Enjoy your PSI/MPG/Ride experiments.

JeffD