Speakers have 2 power ratings.
Continuous Power handling
Peak Power handling
Peak power handling means that up to what extent of power spike, the speakers voice coil can sustain even it is for a fraction of second. It is measured in watts and doesn't translate into the real world power handling. Mostly cheap speakers have exaggerated number of watts stated on the box. To me, its a useless figure.
Continuous power handling measured in wrms exactly depicts that what power speaker can handle continuously over infinite length of time without generating a lot of heat and mechanical damage.
That means to drive the speakers efficiently, we need to feed them the power equivalent to their continuous power handling.
Almost all the head units put out 22wrms at max by their on-board amplifier. If you want power your 80 rms speakers with them, what will happen.
At nominal volume, it will play fine, but when you start to go volume fancy, the little amplifier in the head unit will start to clip the signal (Square waves) i.e. upper and lower portion of signal is clipped due to lack of power. It will generate distortion. The amplifier's power supply may fluctuate according to the demands of the audio signals.