Sorry you are having trouble getting your car started after a big project.
BMW does a good job making sure all the plugs are different sizes and shapes and not giving you too much wire, so it is unlikely you have something plugged in the wrong place. HOwever, it is easy to miss connecting a wire or small hoseduring re-assembly.
Since you had the injector clips off, I would continue to look there. I left the clips off last time and just use the nuts to keep the injector bar in place. The clips kept getting in the way of seating the connectors completely.
Also, were the spark plug boots in good condition? If they are torn or damaged (or not seated correctly) it will let the spark arc and not fire the plug.
Keep us posted