Haha I really really want to swap the tires. But I wont worry about it too much. I've done the LED light conversion to get the lights to look like HIDs and I'm pretty happy with it now. This thing is fantastic! Reading Vman455's post and my car slowly dying convinced me to get the Prius and it was a great choice.
Would a passenger mirror and wiper delete make a noticeable difference, from your testing?