Hey guys, I've been meaning to put a subwoofer in my RS for a while, and I don't feel like spending $500. I really just need a little extra oomf, not a full 12" kicker. Is it possible to buy a factory subaru sub off ebay and install it myself? If so, is the wiring really simple or do I need to pop off the door panel and attach it in there? Has anyone ever done this before?