we recommend 5k for an amp such to match the peak performance capabilities, put 5k continuous power on any sub and its gonna die before i see my next birthday, speakers don't generally do well long term, but short term can be incredibly. For it to sound its best you need to generally match the amplifier to the short term rating. This doesn't help the sub, but rather prevents clipping distortion that you might otherwise experience when you push the amp harder. Having said that, the LMS Ultra will do very well with 2000 watts