this driver is quite similar to the jbl 2242 used in the majority of pro cinema applications.
two drivers in parallel give a net of 4 ohms.
in 8-10 cubic feet per cab (one driver per cab) tuned to around 25hz, one ep2500/4000 amp (with 2000 real watts at 20hz) will hit more than 125db before any boundary or pressure vessel gain.
this would be a crazy good subwoofer setup for around $1k.
if you want to push it deeper, that ultimately becomes an air pump and power equation. i would choose a different driver and much more amplification if that is your goal.