hi i have an 08 e90, with 2 four ch 2200 watt rms amplifiers, 1 two ch 600 watt rms amplifier, and 2 1200 watt rms monoblock amps pushing six 6.5" mid range, six 8" mid range, the stock 4.5" front door speakers and the 2 front door tweeters. and two twelves in ported enclosure that i think is close to 5cft.