A class D monoblock is a highly efficient and more powerful amp suitable for sub-woofers. But they may not be that suitable for speakers/tweeter due to high distortion.
It's how many times a certain gage wire is wound Is the power factor but you would have to upgrade resistors to a higher value. Also would have to upgrade mosfets circuits as well. Would be cheaper...
class c amplifiers have horrible distortion, but well efficiency, and primarily used for small applications that don't need quality playback sound, such as CB radios, walkie talkies, ect....Class C...