More speakers doesn't necessarily mean better sound, but my guess is they are separate tweeters? When I had an Outback (for a few years, terrible car, even with a stick) I put in the factory tweets for $100. Popped right in, wiring already there, took me 15 minutes. They did help with better defined highs. This is probably the one option pulling me to the Premium but seems easily fixed with aftermarket or factory accessory. I see the Prius tires as almost a plus for goofing around on the street.