I just a 15 in sub at my local shop. I tested it out. It's awesome for low end bass. I have a question though. If I took the spare tire out, do you think I could fit a 15 in there. I know the hole is big enough to hold the sub but do you think it will sound good. I'm thinking since it's not in a box it will sound shity, but I could be wrong. Please give me feed back on this topic.