Subwoofer Recommendation?

[JimmyMang]

I have a 2005 Maxima that the previous owner had installed a custom audio system. The dealer restored the system back to factory (Bose) before I bought it. It sounds good but needs more bottom. There is a hole in the back shelf (center) with a speaker grate over it, but underneath (in the trunk) there is nothing. I assume a subwoofer was here. I've looked at powered subwoofer systems and am confused about what I can put in there (size, style and existing wiring). Any advice appreciated!

j

[JimmyMang]

Crutchfield recommended a:"Kenwood SW 100. It's small size and big sound would be an excellent fit."

Not sure about that...