Neither do i think that this is the stig nor is the track closed.
Doubt why it probably isn't the stig / Top Gear comparison: all three cars on this picture are LHD - usually they bring the cars along from Britain, it wouldn't make any sense for Mitsubishi / Subaru germany to hand cars over to them as they aren't covered in german television. The Polo in front could be a rental car but I don't know of any bigger German car rental company that registers its cars in Koblenz (that's what the KO at the beginning of the plate stands for) nor is Volkswagen officially represented there.
I do know that we cannot see the registration number of the EVO, but chances the driver in it being the stig are rather limited in my opinion.