My son has outgrown his convertible carseat. A while back I bought him the Graco Nautilus for my vehicle. My husband was unhappy that I spent that kind of money and wanted a booster instead. Well now my husband needs a carseat in HIS car for my son b/c he is picking him up more often. He is INSISTING on a booster! And what's worse is NO ONE I talk to seems to agree with me! Everyone seems to think a booster is perfectly fine for a 4 yr old. I just don't understand why safety isn't the number one priority. I bought another Graco (b/c it is the cheapest of the higher weight harnesses... I would've preferred something else as I don't particularly care for the short crotch strap in the nautilus) and my husband is ticked and wants me to return it. I keep reading everywhere a 5 point harness is safer but I can't find ANY STATISTICS to back it up so I can't "prove it" to my husband. Can anyone help me out?