Today I took the snorkus off my Forester and realized that the dealership that I bought my car from never installed an air filter. My car always sounded more aggressive and I had thought that maybe the previous owner had already done the snorkus mod. After I took the snorkus off I went to Auto Zone and bought an air filter. After all was said and done my car sounds the same as before, and feels the same. So maybe the two things cancelled each other out, but it should run better now.