This is what I have in the trunk. IMO, you wouldn't need this much bass. A good 10" sub would be fine. I have a Directed Audio 12" dual voice coil, running 900W RMS. It's loud when I want, and just filling the low end when it's turned down to a respectable level. How much room are you wiling to sacrifice?
Of course, the head unit really helps with the total sound produced. Just upgrading to a Sony from the stock one would be an improvement. I happened to score an awesome deal on a Kenwood Excelon DDX 7015 double din DVD for 400 bucks shipped. I've upgraded the door speakers to Eclipse SP5700, witht the front tweeters flush mounted up higher on the doors. Some people don't like it, but it works great for movies. I love the full surround sound it has now.
Total spent on sub and amp:
Sub: 127.00
Box: 50.00
Amp: 299.00 (Kenwood KAC9104-D)
Wiring/blade fuse/etc. : 50.00
Of course, the head unit really helps with the total sound produced. Just upgrading to a Sony from the stock one would be an improvement. I happened to score an awesome deal on a Kenwood Excelon DDX 7015 double din DVD for 400 bucks shipped. I've upgraded the door speakers to Eclipse SP5700, witht the front tweeters flush mounted up higher on the doors. Some people don't like it, but it works great for movies. I love the full surround sound it has now.
Total spent on sub and amp:
Sub: 127.00
Box: 50.00
Amp: 299.00 (Kenwood KAC9104-D)
Wiring/blade fuse/etc. : 50.00