Has anyone done any improvements to the aerodynamics of their Prius? I realize that is very smooth as it is, but even subtle changes can make a huge difference over time. There are a lot of people at gassavers.org that alter their vehicles quite a bit to maximize efficiency. A couple of the normal ICE cars there get into the upper 60s to 70 mpg! One thing that seems to help is blocking over some parts of the grill. This not only warms the ICE faster, but improves aerodynamics, since the air that would have gone through and bounced all over the place is redirectly around the body. Has anyone blocked part of their grill year-round? Weight reduction is also a big thing there, as is turning your car off on down hills and at stoplights (like the Prius). One of the guys there borrowed a Prius for a week and averaged around 75 mpg! Belly pans are also common, which may help on the Prius too. It is smooth underneath there, but it could be smoother.