I'm not even sure why any more... but I tend to put factory mud flaps on my cars. The Prius was probably the easiest installation yet. Purchased from a vendor on eBay. Pictures of the installation have already been generously posted here, so I won't duplicate! My flaps were purchased from Deland Toyota.

The completely stock (minus plastic wheel trim) before shots:

Time to get to work. Though I have a floor jack, I used this opportunity to get comfortable with the tools that come with the car - finding the jack pads and all... making sure I can remove the lugs with the supplied wrench. Everything went well. (lugs were reinstalled with a torque wrench. 76 ft-lbs, right?)

And of course I added the official "unauthorized" extra inside screw for the anal gratification.

All done. Tough to see black in the shadows though!