Yes, I took out both top and bottom of the box. The snorkel attaches to the metal bracket under the box so it stays in place. Everyone kept telling me had to leave the bottom part of the box in, but the filter was too long to fit in the box and the snorkel don't need it to stay in place. I plan to get a SVT snorkel it's a much wider at both the opening and the hose. I also cut out the plastic square just in front of the opening to allow more air flow.
Do one thing every day that scares you. -Eleanor Roosevelt