I'll throw a hose clamp on it and try it without the lid that way.They don't, you don't need one in the factory set up because the box holds the filter in place on both ends. I put a hose clamp on mine when I took my entire airbox off to run it like a ram intake. Shouldn't have any issues with the lid off either because the box still supports it and holds it in place.
I'm amazed at how great these little 2.0's sound. I mean both the intake noise and exhaust.