We have a 2 year old and a newborn on the way. One of the attractions of the X is how easy it is to get car seats and kids in and out (versus traditional SUV doors). How many do you typically have in your car and what are their ages? What about the X is good for younger kids and bad for younger kids? (I am not worried about the "messy" factor). Any help / experience is appreciated about trunk space, mileage, safety, convenience, etc.... when it comes to the X and having kids in it.