J.! Wow! I think you may be the only other mom with this car trouble. I had a SAAB 92x (which I loved!!!), but it was a tight fit with the car seat. I am a major Britax fan (because of the safety ratings and I am a total car seat nazi!) My husband and I are very tall and we drove and rode in that car with the seats alllll the way back which created quite a tight squeeze in the back! When my daughter grew out of her infant car seat at 9 months due to her height we went to Goores and tried out convertible seats in our car to see what would fit rear facing. It turned out (much to my excitement- I got the zebra cover) that the Britax Marathon fits in the middle of the back (rear facing), and of course forward facing as well. It kinda wedges between the front seats and ends up being super secure - no chance of it going anywhere!! It doesn't get in your way when you are in the front, but it is right there. I absolutely love that seat!
I hear people complaining about ease of installation, but most of those people don't properly secure their car seats anyway, so what do they know! If you get trained by a professional to install your car seat properly it is easy! Besides - who cares about installation when it keeps your precious cargo safe! (Okay - I'll just shut up now! ;))
Anyway, The Britax Marathon may be a bit more expensive, but it will last a long time!!! My daughter is almost 4, tall, and still fits well in the seat. I like knowing that she is still very safe and secure in her seat!
We recently purchased the Britax Frontier for my husband's car which has a 5 point harness and converts to a high back booster and then to a backless booster and we love that seat as well...just FYI for the future.
Well....I hope this helps a bit....feel free to email me if you have any other questions!
Good luck!
D. and Layla