[DrLivingston1980]

There are two holes (no pun intended), one facing the front of the vehicle and one connecting to the fender well. The seal on the fender well is pretty darn tight and the opening in the front is to grab the extra air in the engine compartment (according to aFe) because the fender well will not provide enough alone. The sound is noticeable when you punch it down (nice deep growling adds to the already good sounding engine noise.) I saw much more consistent gas mileage readings this morning driving to work. Usually my mileage would jump back and forth from 19.5 to 17's when I went over 70 MPH. This morning the mpg indicator didn't go below 18.3 (peaked at 21mpg) and that's driving anywhere from 55-80 mph. Much better consistency. My throttle response seems to have smoothed out a little as well (noticed this shifting lanes on the highway.) So far all is well, I see gains in both MPG (.5-1 mpg with better consistency) and engine performance. You can definitely tell the engine is liking the extra boost.