Close enough. The car apparently started appearing in 1985, but it was in '87 that Porsche explained what it was. Point duly added!
Here is some info about it:
"In the mid-1980s, a strange matte-black coupe was frequently spotted on Porsche’s Weissach test tracks and occasionally snapped by an opportunistic photographer. “What could it be?” wondered journalists. “Was it a completely new model? A possible 911 replacement?” It looked the part with its plunging nose and big tail-mounted wing.
In 1987, Porsche came clean. This was the Type 2696, also known as the PEP—standing for Porsche Experimental Prototype. Built by the Weissach engineers, the car was their tool for exploring advanced concepts of handling and suspension.
“It’s a rolling test stand,” explained Peter Schutz, Porsche’s chief at the time. “It is a car with which we can do some preliminary feasibility evaluations of concepts. It gives us the opportunity to evaluate different drive systems, because it is literally a Tinkertoy.”