by the way, i just checked the florida seat belt/car seat regulations regarding your 5 year old..
your 5 year old will NOT require anything (other than the seat belt - which is required for all by law)..
a car seat is only required up to and including 4 year olds...
5 year olds are not required to use a car seat..
so if your older boy is actually 5, only the younger one will require a car seat...