this makes my head hurt.
SQ does not have to be sealed. just because its clean sounding doesnt make it sq. SQ is perception though and unless you are on an rta you dont have to worry about it.
SPL is this B%RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP! read the number let the batteries charge up and do it again.
a good reliable daily driver is a combo of both worlds. a nice low tuned box or even a sealed box that plays all types of music with little roll off. match that with a subwoofer or subwoofers and an amp that does the actual RMS rating of your woofers at the correct impedence without clipping. Combined with a solid interior amp for a set or two of components. you can enjoy this on long road trips at high volume levels without fear of blwoing something up.