My husband just installed our new convertible Safety 1st Alpha Omega Elite in my Toyota Prius for our 1 year old, rear facing, in the back seat on the passenger side. He could not get a good install in the center. There is a hump in the seat there and so you cannot tighten the car seat enough to keep it from flopping around. It wasn't as bad with our infant seat (which we kept in the center), but it did flop some. Is there a way to install the AOE in the center? I understand that is safer than a side. Should we get a different seat?