Would love to see anyone's modsHi,
we've got that question a lot. The topliftpro would damage the headliners on it's own, but if you put something in between where the lift actually pushes on the headliner panels you will be good. Maybe a thick piece of carpet would work but better would be a piece of plywood with some carpet on it. You wouldn't want wood directly against the headliners.
I hope that helps,