I had a customer approach me a while back to create a website for his car sales business, at first I thought of doing it in either wordpress or opencart but the client was a little apprehensive about a cms so took a while to work out and instead I did a static site linked to autotrader. Then anotherclient asked for a site for the same thing and I decided to use xara plus ecwid shopping cart, and with some css codes (actually a long list) managed to create the site so that the client can make changes to the 'shopping cart' without affecting the website.

http://www.peterjamescarsales.com

The client has started adding the cars, unfortunately the image file sizes are a little large so could be slow for you.