At one time I thought I saw an option for a Honda dealer installed subwoofer. What ever came of it? Where was it supposed to be mounted?

 

Are you talking about the one on this page? - http://handa-accessories.com/s2000elect.html

 

mine came with one already installed...sounds decent if you have aftermarket speakers/amp installed to compliment it but definately not worth the money (you could get for example JL W3 w/ box with a couple of bucks left over for an amp for the price of the honda sub)

 

It's rare to find any in cabin all-in-one amp/sub to be worthwhile.