Konrad,
I'm jumping in here late in the game, but I just wanted to add that you
really should mount the car seat where they've designed it to be
mounted. While it's more difficult to sit the infant in the seat when
mounted in the middle, it's much more difficult to imagine how you'd
feel if your car was hit on the side you chose to place the car seat.

The middle of the back seat is the SAFEST place to have your child while
in a car. I personally wouldn't compromise that for my own personal
needs.