Warden,

Be sure you really check the windshield and rear window seals. When I got my '84 300 right side carpets would get wet during rainstorms / car wash. Turned out to be the lower corners of the windshield/rear glass seals. They had dried out and pulled away from the metal. Water ran down the sheet metal behind the upholstery panels and under the rear seat so it was hard to trace.

Rear window installation from factory includes a whole bunch of clay type sealant (under the rubber seal) that also dries out.

Pull the carpets, etc., then use a garden hose and work your way UP the car to find the leaks. If you hose the whole thing it's harder to pinpoint the source.

I bought both seals from Fastlane, had a car window guy R/R both. (Also put in a new windshield..what a difference over the original (with 360,000 miles of pitting!).

Drove through some huge T'storms the next day and no leaks!

F