I have to be honest here, whilst technically this is very good, from a customer's perspective and from a "person what works in the industry" perspective, I feel this isn't the best. It's certainly new, but that doesn't mean the user experience is any good.

I agree that the standard "pick a make and model and hope for the best" kind of search is in dire need of an update, but I don't have the UX design experience or even the creativity to invent a new way of doing it, but what I do know, is what currently works, and what doesn't.

Instant feedback on the search as you are performing it is cool, and I've recently worked on a system that feeds back to the user the amount of cars that are going to be returned by their selected criteria as they select them, and it works pretty well and looks great, degrades nicely and allows someone to make a quick judgement about how broad or narrow their search is on the fly.

I'd like to see a new way to search for used cars that merges this level of visual detail with the standard selection criteria based way of searching, and hopefully something great can grow out of that, but until then, mixing up the interface like this will just confuse people.

Apart from my qualms, I do think this is pretty excellent and daring, but not really practical at the current time.