There should be directions on how to use the locking clip in you car owners manual and the car seat instructions. Only 15 out of every 100 people nationally are using their car seats correctly. We would like to find a seat that fits well. These sites are parents offering opinions. My advise to you is to seek the expertise of a child passenger safety technician.
Most car seats do fit in most vehicles.
The level of work needed to achieve the correct installation varies. In the same breath, I am a concerned father about my baby's safety. I think it's a new model. My advise is to go to the Graco website or call them for more info on the seat. Look into consumer reports for additional info on car seats and keep in mind that consumer reports only offers another point of view, there info needs to be a piece of the info you use to help guide you with the decision.