http://www.r2cperformance.com/clear-oval--air-cleaner-base-and-lid.aspx I know some Stock Eliminator guys that run these filters and don't remove them for heads up runs. I ran a K&N oval filter and the filter lid on my Stocker zero performance difference.

If you are running a bracket car, what difference does it make if it slows the car a couple of hun. I would rather jet for it and keep trash out of my engine.