I have a car seat in my 08 and use the seatbelt with the I think the "tite-right" buckle, and even the car seat hooks. What I did for the headrest is just forced the car seat's back latch through the bottom of the headrest, It didn't hurt anything and it is much better than going over the headrest. However, if the car seat is the bigger one, (roughly for a 1 year old or older) get the "tite-right" buckle tightner. It is amazing. And you wouldn't even need to use the car seat strap belts. You can find them at ToysRus for about $15. Might be a different name though.