It really depends. If they get loud enough for you with the given wattage then why would you need more? Also its going to depend on the efficiency of the sub, type of box, vehicle etc. If you already have an amp i say try it first then if its not enough look at getting more power. I run a 250 watt amp to a 400 watt rms sub and its enough for me but I dont listen incredably loud either. Just make sure your below clipping on the amp.