So I think one of my stock subs is starting to go, so I want to replace them both. I want to keep them in the factory position. I've seen two different sizes for those subs, either 6x9 or 6.5. Which is it? If I went with 6.5 subs, will they fit in the hole if the subs are actually 6x9? I need the trunk room, so I don't want to go with an enclosure. Any suggestions?