PCA SDR

Got a Black 911 with lots of top surface deep, embedded water stains.
Any idea of who or how to remove?

Kind of hard to say without looking at the car.
Generally I would try a non abrasive polish first. Klasse "All in One"(sold by your local Porsche dealer) can be pretty good at removing oxidation and lots of surface contamination. You might also try a very mildly abrasive polish/glaze. My favorite in the category would 3M Imperial hand glaze.
If the water spots are severe and have etched the surface of the paint then you will likely need to use an abrasive polish like a "swirl remover" Meguiars makes a good one for dark colored cars.
If these ideas don't work then get a good detailer for more aggressive work.

You might want to try clay first. This might get the spots if they are in the wax. Wash the car first with Dawn dishsoap. It is alkaline and will take the wax off for the most part. Then clay the car. If this does not work I have used a Wax Shop product 'Safe Cut' on my Grand National, you can get it at Coast Car Covers. But use it carefully. Water spots sometimes eat into the paint so good luck.

Like Chris said, start with a gentle cleaner and see what happens. If you are not happy, try a little bit more abrasive one and so on until you are happy. It is often a fine line between spot removal and paint removal, so start gentle and use lots of elbow grease for best results with the least damage.

Mix a 50% solution of water and vinegar. Put it in a spray bottle. Mist the surface lightly and let it sit for 30-60 seconds. Wipe off with a microfibre cloth. Most if not all of the hard water deposit will be gone. Repeat if necessary to finish the job.

It's safe, it's easy, and it works!

I highly recommend Zymol Cleanse. I have found it to be fairly amazing in removng deep water spots -- but if they have etched themselves into the paint, try Griot's Garage Hand Polish.

If the water spots are severe and have etched the surface of the paint then you will likely need to use an abrasive polish like a "swirl remover" Meguiars makes a good one for dark colored cars.

Yes, listen to Chris; he does all this to the underside of the hood of his race car, followed by a few coats of wax of course. And thats no BS.

Thanks for outing me Dave.
I feel much better now that everyone knows about my fetish. At least I don't intentionally put spots all over my car like others on this board! Cars are meant to be spot free!!!
That engine bay really looked beautiful though, didn't it?

An unpainted fiberglass hood cured me....