Soon, Scooby-Doo's Mystery Machine will be eating Marg Helgenberger's dust! In CSI's Quentin Tarantino-directed season finale, viewers will get their first gander at the Mobile Analysis Unit, a new forensics vehicle designed by show sponsor GMC. "We're treating [it] like a new character," explains CBS' David Katz (who's previewing the hot wheels on the network's website). And better yet, a new character that won't call in sick during contract negotiations...