hey hun, I don't have that car, but I have a Rav 4, so was very limited with space. We were able to keep the maxi rider for Emily, but we had to buy a narrow booster seat for Nina and a narrow convertible seat for Ambah. For Nina, we have the Infa Secure booster (I think it's called). It's really narrow, and has extendable head support, so it grows with her. For Ambah, we have a Go Safe something or rather (can't remember the name off the top of my head).
HTH