2010 Prius no JBL

I’m looking to upgrade my sound system in my car and would like suggestions.

I’m looking for more crisp clear sound so I’m thinking of upgrading the 2 front car doors+ a subwoofer in the trunk. I’m doing this all off my 12v battery in the trunk so I’m wondering what the appropriate wattage should be in order to keep everything healthy. Also looking for recommendations on amps , speakers, or subs.

 

Forgot to mention- factory head unit no navigation