Welcome to the forum. Yes the rear speakers can be replaced, but there isn't much point since they're behind the seats. It's far more efficient to replace the front speakers.
There are several options for the subwoofer.
Near the top of the page on the right is a button labeled "Search this Forum." Click that, type in "Stereo" and see what others have done for various model years, budgets, and expectations. You can then make your own trade-offs.
There are several options for the subwoofer.
Near the top of the page on the right is a button labeled "Search this Forum." Click that, type in "Stereo" and see what others have done for various model years, budgets, and expectations. You can then make your own trade-offs.
