I like the Transformers idea...
But then I can offer this:
"I really wanted to drive a Transformer, but all I could afford is this Go-Bot"
"I BRAKE FOR RED LIGHTS AND STOP SIGNS."
"KEEP HONKING, I'M DEAF"
"My sticker has this written on it and yours doesn't, so therefore I must be original and a free-thinking nonconformist."
"IF THIS VAN'S A ROCKIN', I MUST NEED A TUNE-UP"
