"Ziggy says there's a [insert a number here, from 0 to 100] % chance that this is a responsible driver."
Another one could be: "If I ever run over someone with this car, I hope it's Angelita Carmen Guadalupe Cecilia Jiménez."
Angelita was the Angel from the episode "It's a Wonderful Leap", for those who don't remember.
Edit: I just thought of another one, and it could go like this: "I'm not Kitt; I'm not Marty McFly's car; I am not Christine; I'm only... an Experimental Model."
Kitt was the car from "Knight Rider", a show from the 80's that starred David Hasselhoff.
Marty McFly's car is the DeLorean that appeared in the "Back to the Future" trilogy, and it was also a time machine (Marty McFly was the character who drove it).
Christine is the killer car created by Stephen King. The movie was so successful that they even had some bumper stickers around in the 80's. They said nothing more than just "I am Christine" and that was it, so I'm kinda basing this off of that.
And The Experimental Model was Al's car, of course. It appeared in the episodes "Genesis" and "Killin' Time".
It was fun thinking about this.