The factory sound system of most Honda cars is absolutely horrible. Along with replacing the speakers it would be nice to add a subwoofer, however, space inside the small cabin is limited. Putting a sub in the trunk may be popular with folks looking to try and impress those around them but I want good sound in the cabin.
I found the following product from JL Audio called a stealth box that is custom made for a lot of vehicles including the Del Sol. The enclosure simply replaces the back cabin interior panel with two down-firing 8" subs.