Sir
Rated power, RMS or true power are all same. they are the correct standard of measurement.
Kenwood 718 is rated @ 80W for the pair (both speakers).
Pioneer GM4300F is rated @ 40W Rms.
Kenwood 8401 and Sony are both rated @ 60WRMS but maximum power of Kenwood is 640W, Pioneer 400W, Sony 300W .
the above mentioned 3 AMPS are all 4 Channel that means they can drive 4 speaker (or 2 pair of speakers), or 4 SUBS 2 SUBS and 2 Speakers, or 2 Speakers and 1 SUB or any other combinations.
Power on higher side is always peak power or PMPO.
Regards