How do you know what kind of subwoofer goes with what amp?

a 500 watt sub woofer puts out 250 RMS a 500 watt amp puts out the same and if you want a good setup get a sub with RMS and a amp with 1200 max so 600 RMS will be powering the same 500 RMS sub woofer then you can tune it to push the sub woofer a bit and the sub woofer should take it

I recommend ether

mono single channel

2 channel

brands

go name brand if u want support later

or go no name to be different