First thing to is raise the set to full height. Then follow proper shut down and SRS procedures before disconnecting the battery, seat belt needs to be unbolted and you need to be careful with any components under each seat. Remove the star bolts at the rear of the rails and tilt the seat forward enough to disconnect any harnesses going into the seat. Remove the two star bolts at the front of the rails.
Hopefully you have a helper. Tilt the seat so it's "outside" edge is down and the seat back is in the back seat. Carefully rotate it so the front of the seat base is going out the front door first. Naturally the back will follow. I tend to way over protect things I roll the window on whichever side and cover the inner door panel with a moving blanket and cover the dash and glove box on the passenger side. Fully raise the steering wheel so the drives seat can be navigated under it and out the door on the drivers side.
The above is for the 2007 model. not sure which procedure the 2006 follows, but if it is the earlier set up there is very little difference. Instead of four star bolts, you have two standard bolts in the back and two nuts under covers in the front.
No sweat. I have yet to find a 2006 workshop manual as it was a one year production of BMW design and equipment and the first year for Ford's Jag running gear. 2007 was the first full year for Ford designs and equipment.