Audio help for a beginner?

Nillaz

Head units are relatively easy to demo as they are widely available for you to walk into an audio shop and play with. I would recommend looking at Kenwood and Pioneer first.

Speakers can be a much more involved process as sound quality is so subjective and no shop could possibly carry or have available to demo all of your options. My personal preference is for Hertz but good luck finding a local dealer that doesn't have to special order them for you.

Before you even choose a sub you will have to sit down and think about what you want to achieve. Are you looking for the biggest boom you could get, or perhaps you want something a little more subtle? Are you prepared to trade trunk space for a sub box, or do need something more discreet? You will have to give the logistics of this some thought. Start your search with well known brands like JL and expand from there. Sometimes there are lesser known brands that can give you just as high a level of performance (or higher!) for less money.

Your selection of amps will be in part determined by the speakers that you choose since you will want to find one that will drive your speakers appropriately.

Hope this gives you some starting points to work with. Best of luck!