The Alpine SBR-S8-4 is a complete woofer and ported enclosure combo. It consist of a tuned-ported slim design enclosure and an 8" single voice coil 4ohm woofer with a recommended RMS power rating of 150-350 watts and is perfectly within your MRV-V500 amps 150Wrms @4ohm power output capability.

This sub should work nicely with your system.