best sub and amp?

I've had similar experiences at car stereo places.  Sometimes the people they employ blow my mind.  - They have no idea what "sound quality" means.  I was at a store and the salesman was trying to push one brand of components on me because, "they hit hard and play really loud and you can feed them 250 watts each."   I told him I don't listen to music loud, wouldn't be feeding them that much power, and wanted to focus on sound quality.  He kept insisting that these were the best for me and would reluctantly demo other speakers I wanted to hear for me.  This is a prime example of a horrible car audio salesperson.  Unfortunately, a lot of the punks some of these places seem to employ seem to know jack about sound quality. 

However, there are people out there that know what they are talking about:  Luckily the installer happened to walk into the demo room and overheard our conversation.  He then said, "Why are you trying to sell him those?  He obviously doesn't care about the power handling."  This installer told me to wait a few minutes and then he came back and told me what he liked and disliked about how the various speakers sounded and seemed like he was willing to do A/B tests with me all day on -my- music.  It was a good experience and I finally decided on a good mix of price / quality that I liked.

Anyway, my point to the whole story is that some people in the car audio industry obviously don't have a clue about sound quality.  Others do - seek them out!  Another piece of advice I used when looking for car audio:   take in a disc of your music that you are very familiar with and want to hear.  If possible demo it on a really high quality home audio setup before you demo the car audio equipment.  This way you'll know how the cd is actually supposed to sound.    - my 2 cents :-)