The new owner of T326 HU75, Rüdiger Mager, gives an account of it's history that he has been able to confirm so far:
"It was bought by Frank Lampe in 1977 via Andreas Stadler Schwetzingen (A.S.S.).
Fortunately, I bought a copy of the German "Rally Racing (10/77)" journal on eBay, which includes a poster of our car.
In 1978, he sold the car to Manfred Speuser (Munich). At first, he drove the car with an air-cooled engine, then, after an engine failure, he converted it to a VW Golf (Rabbit?) water-cooled engine.
He drove only on the hills, not on circuits. He still lives in Munich.
In the mid 1980s he sold the car and the next owner is unknown (to date).
The farmer of the barn, were the car was located, told us that his father stored the car since the late 1980s so that the (unknown) 3rd owner only had the the car for a maximum 3-5 years. The actual condition (paintwork, mechanics, gearbox) presumes that he didn't drive it a lot.
But now we can 100 % confirm, that our car is the Lampe car, not the Brönnimann car. (As in the background of a picture we have of the Brönnimann car you can see Frank Lampe with our car.)
In 77 there are 2 A.S.S. cars racing, we guess that the 2nd car (Brönnimann) is now located near Nurburgring, but this is another story."
The restoration of the car was completeed in 2016 and it returned to the tracks at the Super VW Festival at Le Mans.