I've heard from Zard they started to produce end of April, and would ship "mid-may". My dealer said they were supposed to be shipped from factory starting the 7th of May.
In any case, they were supposed to be "available in April" when ordered, and I've not been notified of any delay - this is not very professional (also, not lawful, and enables free cancelation), but from my experience, it is unfortunately very common with exhausts/parts manufacturers...