metameme

i have an 05 TSX with stock everything interior except i have subs in the trunk. I'm looking to upgrade my interior speakers so i can have clearer/louder mids and highs. i'm also looking to improve sound quality in the back seat because the subs drown out a lot of the sound for the people in the back. Anyone have recommendations for a good speaker set up that i can hook up to my factory HU?

Also is there a way i can just make it so the volume goes louder? When listening through aux input i have to turn the volume up a lot higher to get it loud and it maxes out at 40, and a lot of the time that's not loud enough.

Any help would be greatly appreciated.