Mono amps only have one channel and are designed to be run around 2 ohms down to .5 ohms depending on parallel vs. series wiring and the subs that you have. With other amps, you might have to bridge channels to get the correct ohm stability. Generally class D or Mono amps will be able to withstand more abuse since they are specifically made for subwoofers. Multi channel amps can be wired to run subwoofers or full range speakers.
