you are talking about the gasket w/ the mesh screen, right?
The mesh screen evens out the airflow across the inlet tube and allows the MAF to get a more accurate reading. You can try to run with out it, but if you get an unstable idle, or any other driveability issues, you should add it back in.
Hmm i do have a problem with pulling up to stop signs every once in awhile and the car just stuttering and dropping down to like 500 rpm. I thought it was just the cold, but its been doing it more recently in the warmer weather now. Could this be a not having the screen? Otherwise the car runs ok.
It is a possibility. The screen evens out the flow coming into the MAF, and when the flow is uneven, it is most evident at idle. Try re-installing your screen, and see if things improve.
Either return to the stock configuration, or make up something that will allow you to put the screen back in. Spend a few minutes looking at it and thinking about it, and you can probably figure it out. Maybe something like, measure the compressed thickness of the rubber gasket around the screen, and get four washers of the same thickness, or slightly less to put one at each bolt where the adpater bolts on to give enough clearance for the screen to clamp in place . . . or get fancy, and machine up a full size shim that holds the screen in place to bolt the shim and screen into location. . .