For those of you who don't get to the electronics forum very often take a look at the thread regarding the custom 8" subwoofer enclosure. I am amazed at the ingenuity of the members of this board and this product is great for the S2000.
Wlaurent has developed an enclosure that blends in perfectly and takes up virtually no room in the trunk. It improves the low bass dramatically and will take the frequency response down to 40 hz. The past two years I have been using a Q logic box which sounded fine but this approach is much better.