I'm going to be replacing my headliner in the near future and had a few questions. My current headliner is torn at the seams in several areas , so I plan on simply buying a new headliner and installing it. My question is do I need any special tools and what kind of headliner do I need to buy? I think I have all the cross member spans that can be re-used, so I assume they just thread through the new headliner. I've also read something about sails, but am not completely sure I know what it is referencing. Can someone provide me a little guidance and help me understand what I'm getting into. Thanks!!