I’m like you – want good sound, but doesn’t need to be “Kyle”good.
I put in a box with a 4 ohm kicker sub in a box and it sounds great. Of course, I dont have any storage space under the observers seat, but i dont need it anyways.
As far as music, if your receiver has a USB, I highly recommend a flash drive full of your music. saves your cell battery, and sound quality will be much better.