You have that backwards; sealed alignments play lower than ported. Bass reflex have more output, specifically above port tune, but due to their respective roll off characteristics the sealed alignment drops at half the rate of a ported subwoofer. If you want extension, you want sealed. It...
What are "frequency spans"? I've never heard that term before.
Is this a reference to the physics behind acoustic suspension? If so, there is no 'speed' (faster) associated to resistance. Resistance to movement is a measure of force reduction, not static positioning.
A low MMS (super lite...