The easiest way to answer this question is to glance at the Wikipedia page for the Integra. Considering the popularity of Hondas, if there was even a significant rumor of a V6 Integra it would probably be there. It's not.
Some Google-fu for various permutations of V6 Integra didn't give any results either. There's a few V6 Acuras out there, but there wasn't any version of the Integra with a V6. I want to know what Autozone you went to where this guy was working, because I don't think I wanna shop there (and I love Autozone.)
