Hi Richard, check out my post entry #22 search "started my ims upgrade 2000 s wit 107,000 miles
Takes 5 minutes to make a perfect tool and you can adjust the depth a little if you have any issues on the surfaces. 13mm was the correct depth from the crankshaft face.
The Porsche special tool was big bucks and I couldn't find anyone other then shops that had it.
http://986forum.com/forums/general-discussions/36476-started-my-ims-upgrade-2000-s-wit-107-000-miles-2.html