good day every1!!!

any1 here tried using CRYSTAL subwoofers?
i have 2pcs CMPX215 and m planning to join our upcoming local SPL competition here in the philippines. i need to know what type of box and volume should i use. SPL application. it will be mounted in my suzuki jimny's rear cargo space. ive already removed my back seat to accomodate these 2 woofers. both woofers wil be driven by 2 CUTTING EDGE CE1000M [email protected] mono amplifier bridged together to produce 2100watts @ 2ohms mono. ive upgraded my alternator and installed a 240ampere LIGHTNING AUDIO battery islotor to support 5 SVR batteries. all necessary wirings and components are now in place. subwoofer box is wats left to solve.

ur advises will be highly appreciated.

thanks in advance.