Thanks for you comments. The main idea of the site was to get users to the vehicle they are looking for in as few clicks as possible. I'm very happy with the backend/functionality of the site however the design is some what blah due to the client picking font colors and such. Main thing that needs work so far is the initial download time. Although not really slow it does take a second to dl all the thumbs for each vehicle. After initial dl though the site is very quick due to the ajax calls and all images are already cached.
Id really recommend you take a look at mootools if you are i need of a javascript library for ajax. It is extremely light and easy to use. It will do pretty much everythign you need it to do.
Thanks Again!