the amp is built into the sub enclosure.
The panel and the sub/amp are separate pieces, not sold together. the panel can run up in the 700$ range and here is a link to a nearly 600$ stock woofer.
http://www.courtesyparts.com/2....html
This is great if you want to keep it stock-ish but unfortunately very expensive. If a person wants minimal bass that this will provide without spending the money, a bass tube with an adjustable built in amp (stock is not adjustable) will do the job more than adequately less than half what the panel will cost you. Or the junk yard is always an option... one never knows what they will find!
the answer to #4 is yes, but not what your describing. this is all included in one six pin connector, colored differently.
This is an easy install after the rear seats are removed, plug and play.
Hopefully you get the answers you are looking for. Good luck.