Which infant seat REALLY is best for small cars? (answer will surprise you)

Consumer Reports, in their April 2014 infant car seat ratings, commented that the Britax B-Safe is a "good seat for small vehicles". Consumer Reports also commented, with regard to the Graco Snug Ride 40 Click Connect, that the "design and length of the seat can limit or preclude installation in some vehicles." In their ratings of the Cybex Aton & Aton2, Consumer Reports did not comment one way or the other about whether it was good or bad for small cars.
Here's what is puzzling. The Britax B-Safe and Graco Snug Ride 40 Click Connect take up the SAME amount of room into the front seat (and are also the same width) - but Consumer Reports thinks that one is good for small vehicles and the other isn't.
What is even more puzzling is that the Cybex seats take up 4 inches LESS room into the front seat than the Britax or the Graco... yet nothing is mentioned in their ratings about this rather important compactness feature of the Cybex.