Chigster said:I've had the same thing start on my Targa - a lot of condensation and I mean a LOT. Enough to soak a hand towel once I've wiped down the windscreen and glass roof.
Will investigate this weekend and report back but I am suspecting worn seals on the rear window or roof.
Have a read through this ..
http://911uk.com/viewtopic.php?t=116450
You need to pull the rear carpets to see if its damp there , the very back ones under the tailgate ... if under the rear seats then the front glass seal is suspect .. the tubes break off and water can drip onto the rear seats .
usual fault is blocked rear drains though .