IF it affects the car it is only at idle. There is no performance lost without it in place. Some cars have issues with it being removed at idle and others do not. My bet would be you won't notice it's gone. I recently pulled mine out since it had 250k miles on it it was getting very brittle.
To put it back in just place the sceen in and compress the ring and slide it in to hold the screen in place if you want to use it.
It restricts air flow by about 10 CFM from the numbers I have seen.