Just bought a 2006 Jeep Liberty Renegade. I'm gonna take my 528i in to carmax and sell it for some money for a new system. I'm not sure how much I'll have to spend yet but I was hoping I could get some research done before I set an official budget. I listen to mainly classic dubstep and electronic music that has really, really heavy bass (I'm not talking skrilllex or Doctor P midrange bullshit/midrange dubstep.) So my main concern is taking the bass to the next level. So I've done some research and am more comfortable with the terminology but I still have a couple questions. I'm assuming its going to be necessary to replace my stock amp to power some new subs, but do I necessarily need a new head unit? Can I just add on an Aux cable? Are there some retail stores that are more reliable than others as far as installation is concerned? (not quite handy enough to trust myself with wiring on my own) Are there any common mistakes I can avoid at this stage (brands to watch out for.) I'll be sure to tack on any questions as they come up. Thanks for the help guys.