John: Regarding your subwoofer question, get an amp. What you need is preferably a "four-way" with RCA output jacks and a subwoofer channel. This will regulate flow to the proper speakers and make you system sound better. The highs (tweeters) will not be "clipped", and the lows will be divided between your stock woofers and the subwoofer. If you want the best sound, pay a little more. The Judge