I hate to brag about my grill.
http://www.sonicelectronix.com/item_...che+SSG12.html
I mounted two of them, one spinning clockwise and the other ccw. I painted them "interior beige" and mounted strobe lights that flash at different intensities, depending on the bass output. The strobes "freeze" the spinning grills, presenting a solid appearance that will, I am sure, discourage thieves.
The spinning action also throws the sound out into the interior, thus intensifying the bass.
I would post photos, but the intensity of the many strobes just wipes out my digital cameral.