I want to start upgrading my 2008 outback v. I would like to start with increasing sound quality and loudness and adding bass. Tower speakers will be next year. I have the basic six speakers and amp. I would like recomendations for sub, and pre built sub box, and amp to power. Also to replace factory speakers with something better. Thanks for help. If you have an outback and have pics your system that would be very helpfull.