We had two kids (newborn and 3) in car seats and a Ford Focus. The other car was a Jetta.

The Focus even had a small aftermarket amp and sub in the trunk. Everybody and their things still fit, although the sub did come out for long trips for that extra cargo.

The Golf Wagon that came later still fit us and the dog. About 90lbs of her would fit in the back and she could drool all over the kids.

Sometimes I wonder what I am missing.