Keep in mind that the factory shroud has a very important job of directing the air around the back side of the cylinders while the car is in motion and the fan isn't running. Without the shroud there is no air movement over the fins around the spark plugs while the car is in motion.
Yes, this was explained to me by Mark Baldwin and finally persuaded me to go with the standard factory cooling solution (even though my engine had never gone into skip-fire mode). Also, it was surprisingly inexpensive at £125+VAT...
