I had a few questions about sealing off the box when you fire foward in a car. I turned my box around to fire it in and its MUCH better, Not as low but way louder over all. My question is , If I open my trunk its WAY louder but at the moment its no sealed around the box. When its actaully sealed would be similar to when the trunk is open now? Doesn blow foam work well to seal it up? Thanks