Originally Posted by Kev

The removable panel is part of the filtered area of the airbox & would need the air to be filtered, if using this lid.

The vents I used are not filters, they allow full unfiltered air into the airbox up stream of the air filter. Manly to get the most amount of air to the air filter. If you remove just the air snorkel the filter is still very restricted. The air drawn into the airbox should be equal to the filter area, but it is only half, if the snorkel is removed. So drilling extra holes make sense.

You can buy 30mm rubber grommets from any hardware to block up the holes when you sell your bike.