What all do you need to upgrade when putting in a sound system?

Question

i am looking to have good bass but to also be able to understand what they are saying.

Answer 1

here is the deal for good bass you will need an amp and a (subwoofer)s with the wiring kit and the sub box.

how ever if you want to to also hear mid bass (vocals) i highly recommend buying 2 pairs of speakers to replace the sock ones and  a separate amp to power the car speakers, because if you were to power them from the head unit without and amp then when the bass hits it will drown the lyrics. but if you use an amp it will sound way better it is costy but it is totally worth it.