I did some testing a few years ago, watching IATs closely, and taped up the perforated lid to make it solid back to back with it untaped to leave it slightly vented, it actually made very little difference. Bulk of the air was still drawn through the fender and lower scoopopening, IATs were only a few degrees (1-3) higher with the lid open vs taped.

If your at the track, definitely remove the lid totally. At WOT it does become a slight restriction only allowing air in through the 2 box openings and the vented lid. The lid wide open helps uncork it a tiny bit.