If it looks somewhat innocuous, that's intentional. This prototype was so far down the path of development that the company's test drivers were evaluating it out on public roads, and they didn't want the world to know what they were up to. A lot of Porsche's die-hard fans are probably mortified at the thought of something other than a traditional flat six going into a 911, but the potential performance could've been astounding.
Aaron Miller is the Rides editor for Supercompressor. He's convinced that all vintage cars should have a V8, but that won't get him to start drinking V8 juice.