Can someone tell me a little about the total harmonic distortion value on amps as far as what the max acceptable level should be & what I should look for on one? I have seen most mid range amps at around 0.02 to 0.05. Is this something I need to concern myself with or is the difference going to so little I won't even notice? Thanks

For most solid state amps, the THD+N values are going to be well under 1%...and of course, what you actually hear is dependent on frequency. You can hear 3% THD much easier at 1 KHz than at 50Hz.

Don't even concern yourself with the THD figures. Any quality amp will have distortion that is within the inaudible range.

You'll hear no difference between .05% and .002%, and you'll hear no difference between .9% and .002%.