I have 3 L7's "12" in a 96 Impala with a memphis mojo amp. I had a custom Ported bandpass box in the trunk where they tunneled a port into my back dash. Now I know that kind of setup is what works best in those cars, but my box cracked so I'm having it rebuilt. Do you guys have any suggestions on what gets the best sound and SPL with that setup? What I had before sounded it great until it cracked. Oh yeah when the installer took out my box I noticed the subs were firing down whats the reason for that?