Thanks for pointing out Roger Kraus Racing. I got in touch with Roger yesterday. The CR322 wasn't very familiar to him but Roger would have tried to get them for me (10-12 weeks lead time). On the other hand he had a set of Avon CR6ZZ 185/70R13 in stock which I bought. Should get the tires in a week or so. Quite expensive ones, indeed. USD 239 each. But Roger talked highly about them. Let's see on how they work out for me respectively the car. BTW: Roger was very helpful and professional.
Arwed