I usually refer to my vehicles by their factory given name, but I'm having issues with the 2 Bronco's cause no one ever knows which one I'm talking about.
Far as gender, I'm kinda falling into the it's an "it" category. If I had to choose they are male, 4x4's seem more masculine to me. If I had a car I guess it would be a "her" but the day I stoop to buying a car I want my head examined anyway.