Which Woofer&End Stage

Hi guys I had a question, I have a fiberglass side part subwoofer for my 3 gulf with a little more than 30l volume (see picture) And wanted to ask now what would you recommend to me in the still more inexpensive segment for a woofer or which amplifier to add to it? A woofer that I would like (only from the optics) would be e.g.: http://sm.crutchfield.com/…/ProdView.asp?… Should be a bissi for the eye 🙂 Bzw. what would you recommend to keep the box closed? Eifen or bass reflex? Anyway. Thanks, Lg Martin