my daughter is 11 months old now and I can assure you the mustang is fine for transport. My wife and I car pool everyday to and from work. We take the stang 3 times a week and her truck the other 2 (gas mileage). It's a little tight but my wife (5ft 6inch) sits comfortably in the front with my daughter in her seat in the back. Do yourself a HUGE favor. Buy and extra base with the infant seat. This way you can keep the base in both your cars and you don't have to keep buckling the seat in and out. It just latches to the base :-)

CONGRATS.