I would really appreciate a box design for 2 15" Memphis M3s. I don't know much about the subs. I don't know if I would get better results from subs/port facing back or subs up/port back. What ever the general consensus is, I'll roll with that. My explorer is 41" wide, the box 18" high, and the depth is whatever for airspace. I would like the box tuned to 33 Hz. Sadly, I don't know the recommended airspace.