Hi,None, better to have more power on hand than what you will need rather than under power your speakers. Now that doe'nt mean go nuts and turn the volume up past the point where your speakers start to sound strained or distorted. Keep in mind the A51 is a beast of an amp, I have the A21 which is 250x2 and my speakers are rated to handle 400 watts and I have pushed my system hard at times but have not reached the limit of amp or speaker! chicken I guess! Should sound great enjoy!
