i dont think the amp will be affected
You are obviously not "au fait" with impedance matching, and it's effects when you choose to ignore what the manufacturer says their equipment needs to see.
not being funny but ive been doing car audio installs for many years
ive got a trophy from db drag to prove i aint no rookie
neither am i questioning the advice given by some members here, as theres a lot of people here with a lot of good knowledge
but when it comes to car audio i do think i know what im talkin about
and coming back to the point if the panasonic speakers are rated at 16ohms then i would again say connect them i will guarantee you will not blow either the stereo ic nor the speakers
the ic are designed to run speakers at 4ohm and not less
nothing stops you from connecting a higher impediance speaker the ic just wont work at its full potential