You actually don't have to drill anything to run the power wire. In the firewall, on the passenger's side, there's a hole with a rubber covering on it. Take the rubber cover off, then just run your power wire through there. You can fit any size wire through there. As for the JLs... I don't think a W6 will fit behind the seats. I think it's a little too deep. Plus, I think they suck. They hit hard, but it's not all about SPL. I like clean bass, and I think they give you anything but. I would go with a Boston Acoustics or an MB Quart (which is what I have). Good balance between thump and clarity, and they handle buckets of power. For a 10" Boston or Quart, they'll run you $200-$250 for the woofer.