I like the design, nice and clean.
I'm not sure what the purpose of the site is. Are these cars for sale?
I don't like the font in the search button.
I don't understand why the nav has: Home, Cars, BMW, Audi, Jeep.
I don't like how the "Make/BodyType" tabs work on hover, I'd rather they worked on click.
I don't like how the car images are skewed. Maybe look into ImageMagick to detect image dimensions so you dont skew them.
Please review my site: http://www.codingforums.com/showthread.php?t=274641