This is the Isdera Imperator 108i. No DT or Pantera connection whatsoever.
It is a development from the MercedesCW311 prototype from the late seventies. The engine was the V8 from an S-class with a manual ZF. If I remember correctly it started life as a road car from German tuner Buchmann & Buchmann. They made some wild Porsche and Mercedes conversions.
Later on it turned into the Isdera who made their own Mercedes based exotics well into the nineties.
I saw one a couple of years ago and it has the same wow factor in the flesh as a Countach.... and a Pantera too ofcourse!