For check the drains, firs open the sunroof. Then open the engine lid. If you see were the struts that supports the lid and the spoiler above that (not in the engine compartment) they're an hole that came from the body. The car have 2 drain holes. One in the left and other in the right. This hole conects with the sunroof area. In the back of the sunroof compartment you will see the holes. Ok those hole get dirty and all you will do is to take some heavy wire and introduce it throught the hole until it exist abobe the engine comparment. Repeat the in-out motion afew time until the friction reduce. I think that the sunroof compartment have another drain holes in the front and it drains in the front fenders, where the door connects with the fender. If the hole are clears, maybe some water is coming from the rear quarter windows or the rear wildshield. The problem of the quarter window is that the rubber seal that sorround the aluminum frame doesn't seal very well. An easy way to check where the water comes is with a garden hose. Take some friend that wet the car with the hose and you go into the car and chek the leaks. Another places where the water can enter is from the doors. Do a carefuly check with this method and dont forget to clean the drain holes. Use a vacumm claner to take out the water from the carpey and buy baking soda, put it in a glass, or bowl and let if inside the car. The baking soda will take away all the swamp odor and absorb the moisture. Leaving you car, with the Porsche classic smell.
I think this can help you,
