This was one of my all time fav autosport videos growing up. It aired on ESPN, and thereafter was rather difficult to acquire...until the Internet came along, when a few 'over the air recordings' were uploaded to the web.
But before any of that occurred, I managed to get hold of the right person, and requested a tape copy of the program. They sent me a VHS with TWO episodes, The Unfair Advantage, and Speed on the Autobahn (begins at 24:50). The quality is not HD obviously but is quite good, though the audio level is a bit low for the second episode. I am guessing the autobahn episode followed the week after the Unfair Advantage episode, but I don't have a date for that release. Here are the credits I received with the tape:
CLIENT: 303 Studio
TITLE: The Secrets of Speed: Audi - The Unfair Advantage
LENGTH: 24 minutes 50 seconds
DATE: 04/19/1990
PRODUCER: Davey / Bulkley
EDITOR: Markgraf
PHIPPS & CO., TULSA, OK
Following Episode:
The Secrets of Speed: Speed on the Autobahn
LENGTH: 25 minutes 25 seconds
The second episode may or may not have the same production details.
Enjoy!