Henrycai, It all depends on the size of your listening room and how far you sit from the speakers. I use the P3ESR(sensitivity a low 82 DB) with 50 watt tube amps with no problem. My room size is 20x15. I have used larger floor standing Spendors with no problem. I have used big solid state amps in the past and I think power is way overated. BTW, what is the size of your room?