Originally Posted by JohnD

$175 for a box is quite expensive, even custom. You can find boxes online for less, try sonicelectronix.com or just use google search. Also you can replace factory door speakers with quality speakers for less than $100, my Alpines were around $75-80 and they take no time to install. I would replace your head unit, door speakers, and if youre not looking for serious bump you can put a single 10 or 12 under your backseat without having to get a huge expensive amp, use ebay, really good amps $150 and up, lesser amos are $80-150. If youre not going for serious sound and serious bass you can get a pretty good system for $500 or so.