I'd assume so... might have to cut a connector off a wire and slice back in.
So long as the existing speaker isn't powered off the head unit... if it's a powered line, you might fry the new speaker.
Sub is easy if you have a factory output/plug.
Otherwise we would pull a lead off one of the speakers and use an inductor to cut out the high frequencies. Maybe it was a capacitor... should check my old book.
This was the mid 90s technology.
Yeah... my springer NM rifle gets checkmate mags. They have been fine in a shoot-off-the-range-bench sutuation. Factory mags are priced like freaking HK.
Dad used to piece together M1A mags... bought bodies, springs and followers from different places and ended up with $15 mags from mostly surplus parts (he said). No idea if that's still a good price these days.
I got on team CZ and got rid of a bunch of stuff. Kept the glocks because I'm so heavily invested in mags and holsters. Most of the CZs will fit ok in a glock holster.