Porsche is beginning to realize that it's sitting on a goldmine of automotive history with its secret vault full of rare cars. Autoblog toured it a few months ago, and we were amazed at all of the curiosities hidden inside. Now, it's starting to let more folks in thanks to a new series of YouTube videos. The first covered the 965 prototype that shoved a water-cooled, Audi V8 into one of its cars. Next up, a mid-engine 911 that acted as the powertrain test mule for the Boxster.