If you have a Generation III Prius (2010-present) with 15 inch wheels, you can pop off the UGLY wheel covers to release the alloy beasts underneath. Except - you'll have a hole in the center of the wheel that begs for a decorative cap. These are based on precise measurements of Toyota part #42603-52110.
This has the symbol of the Autobots: "
Few beings think of themselves as evil. Many justify their actions as good, even if they are not. But if you believe the 'good guys' would not harm any life-form, then you may consider me a member of that team." http://tfwiki.net/wiki/Autobot
Nylon is NOT UV stable. For maximum longevity and downright good looks, you will want to paint this object. Acrylic paints with a glossy topcoat are a proven method of painting objects printed using Selective Laser Sintering.
Shapeways has a tutorial here: http://www.shapeways.com/tutorials/painting3dprintedsls And a blog entry here: http://www.shapeways.com/blog/archives/129-painting-your-3d-printed-models.html
Further, you can locate the recommended Tamiya paints here: http://www.tamiyausa.com/dealers/index.php