I think I've found the source of my leaks and it's the sunroof. To diagnose, I pulled the headliner away from the A & B pillars so I could see what was going on, then I hit the perimeter of the sunroof with my garden hose, which shoots about 50'. I instantly had leaks on both driver/passenger side and water was running out of the headliner where I'd pulled it away from the pillars. To be fair the drain channels were working & I had water coming out of the drain tubes, but they couldn't cope with the flood I was giving the sunroof.

I also hit the roof rack at all the various holddown points, but that didn't seem to add to the leakage. I had previously resealed the roof rack with silicone and had "some" confidence it wasn't leaking.

To prove it was the sunroof, I taped it off from above with packing tape so there were no gaps between it and the roof. I then hit the same areas with my garden hose and voila, no leaks. Now I may selectively tape off one side at a time to see if I can narrow the leaks down. I know the rear of the sunroof has leaks because when I look up into the cavity I created by pulling the headliner away from the B pillars, I can see light coming in at each rear corner.

 

So this AM I taped off the front, right & left, & rear edges of the sunroof and selectively drenched each portion. The front, left & right edges when drenched did not leak at all, but when I removed the tape from the rear edge and drenched that, there was heavy leakage into the car interior & running down the B pillar.onto the floorboard & carpets.

After a close inspection of the rear edge of the glass, it was obvious it was not fitting tightly against both rear corners of the roof. Here are two pics from the driver's side where I had pulled the headliner away from the B pillar and you can see a bright spot in the 2nd pic. That's where the sunroof glass is not fitting against the roof in both rear corners.

Sorry about the orientation, need to rotate both images clockwise 90 degrees to view them properly:




So now I either have to replace the sunroof seal (which I don't really think is the problem) or I have to find some thin weatherstripping or similar to seal these corners. Anyone have a similar experience?