Be aware that if you cut holes in the filter box directly into the engine bay, that you will draw in hot air warmed up by the hot engine, which will have a slight negative effect on the performance. Ideally pull more air into the filter from the fender well by a ram air tube of some sort, or try to find a path from in front of the radiator to the filter. Your engine will like the cooler air much better. Another option is to modify the air filter box, after cutting it open, by sealing the engine bay from the filter with a built up wall of some material, from the filter to the radiator support and form fitting(sealed) against the hood and fender.