I recently bought a car, but while looking I would have liked to have a comparison tool.<p>I wanted to filter on price, color, and than see cars next to each other, to see how they look. They would have to be to scale. Hopefully you could also drive it around a little in the virtual space, and see how they accelerate vs. other cars, how wide are the turns, etc.<p>Now filtering on price does not mean that I want to see cars in same price range. I would have liked to see all sedans in one price range, and minivans in another (I was not shopping for suv, but that would be there too). So basically you should be able to group cars, and filter by groups/sub-groups.<p>I wouldn't pay for the service, but I would have bought a car from this service. I used carsdirect.com in 2000 to buy a car, and tried to use it now unsuccessfully, went through truecar.com instead.