Yes, I forgot. But I remember many warnings about the generic parts.
Well, in my case - rubber from MB as long as affordable. The rest: first choice is MB and, as well, the price comes in. When I needed 12 valve tappets, I just bought Febi.
I think there are many parts without a star on them with great quality. Many of them are generally recognized for that.
In this particular case, rubber, I would go for MB, but I have not checked the prices.