my RX typically sits unattended during the week, locked in the driveway of my second home. if it has rained during the week the front passenger side floor will be soaked, and I can't figure out how the rain gets in. if a door or window or the sunroof wasn't closing properly I'd hear the wind noise on the highway, but I don't. anyone else have this issue?

 

The water gets in through the bolts of the roof rack, ask me how I know. I had the same issue, mine was in the rear. Cheapest fix is to seal around the base where the bolts go through. Will work for a while but will start to leak again eventually, then you need to re-seal again. It has worked for me.

 

Were there marks on your headliner...?