Hey, welcome aboard. I too have a new baby 3 month old daughter. She just loves to go for rides in the car - just like daddy. I have a simple Graco Clickconnect car seat and it fits very well in the Q3. I put a towel under and behind the base so it does not leave an impression in the leather seats, then lock it down tight. It's installed on the drivers side so I can still fold down the larger side back seat. Getting her in and out is a snap. I can also snap/click it into the Graco stroller (which fits in the fold down side) so we can go anywhere without having to remove her from the seat. Works great! She's really happy with the Q3!
-Andy