Distortion in amps;most/least annoying?

Right now I'm looking to add sone second order distortion to the upper mids. Might bias the drivers hotter. Intrestingly my speakers (Omega) are wired with bigger gage on the positive than the negitave. I wonder?

Any kind of coloration. Enhanced mids, rolled-off highs....
I don't need the the amps to interpret, filter or exaggerate , just amplify as honestly and competently as possible. It's not always pretty and it's easy to be tricked by a convincing liar.