2013 upgrade questions

Alright I've had my Tacoma for just about a month now. I'm a little disappointed in the stereo sound quality. My question is can I add an amp, sub and speakers to my stock Entune non-nav head unit? I like the stock head unit and don't see a need to change it, just want to supplement it. I was thinking of adding one sub and amp with a couple of 6.5" speakers to add a little something. Thanks!

 

I added one of these http://www.kicker.com/hideaway to my stock head unit. I have an Access cab so I didn't have much space to work with and Entune wasn't available in the package I ordered. It is tucked under the passenger seat and supplements just the right amount of punch so that my mids can keep up. Very affordable space efficient bang for your buck. And easy to install.