To protect the intake.
This part keeps anything, even a collapsed air filter from entering the intake manifold. Considering the high state of engineering of the Mercedes models, I would assume this screen does not limit the intake volume. I believe that you would get no power increase by removing it. K&N air filters claim to increase air flow and power, but there have been posts and discussions that lead me to believe that it does not increase anything but intake noise. Although I really want to believe that the air filter can increase power, there is no evidence. Also, it lets larger particles into the intake, which could increase engine wear. I think you need to do a lot more than that to increase the engine power. This is my personal, unqualified opinion.
'85 500SL Euro