The large opening EX is 100% open to the sleeper behind the driver’s seat. This kit is a one piece Fiberglass panel that is very easy to install. When we designed this model we chose to add 5” more leg room to the design. We also chose a body line pattern that adds real style to this cab design. You will bolt this kit right into place.  The small opening EX is open in-between both seats and does not give extra seat room.