UPDATE! No wonder both 906 camshafts look "incredibly the same", they were made by the same company! It has been brought to my attention that this photo gallery contains a few error's. The listed "Shrek" camshafts being "aftermarket" and from "England" is completely WRONG. In fact Dr. Schrick GmbH. is a subcontractor to Porsche and is located in Remscheid Germany. My apologies for any confusion on this matter. Here is the link to the "SCHRICK" website (in German) http://www.drschrick.de/ - (in English) http://www.drschrick.de/english/index.php - Take a look, I think you'll be impressed.

Regarding the Schrick cams: They are the manufacture of specialty camshaft products to many German car companies, tuners and several factory competition racing cars. You may of heard of a few of them Porsche Motorsports, BMW "M" series, Mercedes "AMG" just to name a few. Their products are second to none and supply small quantities for special applications for many factories. The issue of a raised casting number or a stamped number are only superficial and they are in my eye's one in the same product (I believe Carl Thompson has already said the same thing to you). As you may already know, that Porsche does in fact not make every part on the car. Let's start with the engine, Castings and forgings are usually done by Fuchs, yes they also do the wheels, Pistons & Cylinders by Mahle or Karl Schmitt, Valves TRW/ATE, Valve springs, Cams & Rocker Arms our friends at Schrick, Filters by Knecht & Mahle, Ignition & fuel injection by Bosch, Carburetors by Solex, Zenith and Weber. Clutches by Fictel & Sachs, Suspension by Koni, Bilstein and Boge Ect.