sundown psi

So heres my situation. I have a 2004 Mazda 3 non hatchback. I can only fit 2 12's and even if i could fit more or less I want 2 12's nonetheless I wanted to buy 2 Rockford Fosgate t0's and put them in a sealed box for an sq setup but I also want spl. Ofcourse the loudest ive ever heard was...