For Future Release: add in a 4wd filter?

[chris-]

When browsing through the website on certain models of cars with optional 4wd or awd, say Jeep Grand Cherokee or Ford F-150, can you add in a filter (similar to engine/body style/trim level filters) that sorts out 2wd vs 4wd models?

There is almost always a noticeable difference in mpg between 2wd and 4wd models, and I think it'd be very helpful to be able to separate them out to better compare "4wd apples" against other "4wd apples," or to see how much difference in fuel economy there is when selecting the 4wd option!

Thanks!
chris-