Boosters and crossovers are at one point can enhance sound quality. However, if setting it to all your stereo and amplifier, this will actually cause the frequency to be misaligned, rather than aligned. Thus, for instance, if you would want to boost your bass, you must also only do this on one component only. Otherwise you will increase the distortion from your subsystems or worse ending up damaging them.
Avoid the possible things that would damage or put your car into a worse situation and rather just improve your system properly. There are a lot of materials everywhere. Feel free to research. But to sum it up, to fully improve your stereo’s sound quality you will need to invest in a quality system and accessories.
