2015 Prius Audio makeover

I'm planning on doing a audio makeover of sorts to our 2015 Prius, and I'm here for any do's and don'ts you all might have for me during this process. The only thing I know I want is a Kenwood Excelon DNX995S (comes out in March), which I know is a crazy expensive radio, still, that's the radio I am going for. Other than that, I have no idea what speakers I should be looking at, I don't know anything about amps or if I want/need one, or if I should add a sub. Any and all help would be appreciated.

Current set up is the 6.1 Nav screen with no JBL equipment.