Thanks guys, this helps quite a bit. The wetness is in the front-right corner of the passenger wheel well...aka if you were a passenger in the car where your right foot would be. I left the car out in the rain last night and it seems to have gotten wetter; to me this suggests it's the windshield as I'd need some airflow from the moving car for water to get across anything in the firewall or inside fender... does that sound correct?

Rob