Not sure what happened, but I had three baby seats in the back of my X3 at one point. It was a tight fit and had to move the seats up but it worked.
Typically, had one car seat and it was dead center with no issues whatsoever. It was a Graco. I had a full five point harness (later on) as seat as my daughter is teeny (only 44 lbs) in the X3 right up until I got rid of it a month ago.
One of the things I really liked about the X3 is the ability to take a car seat in and out with minimum fuss. All of about 2-3 minutes. Sorry the newer one is more difficult.
2013 S4 Loaded (and NO RFT's) Awesome is an understatement
2008 MT X3
RIP you were a faithful sidekick and will be missed.
2007 AT X3 RIPOS
2000 Jeep Cherokee
1997 Twin Turbo RX-7
1984 GTI Wolfsburg Edition Neuspeed and more