Thanks for the input. I have already contacted to this seller via German eBay. This aftermarket fiberglass diffuser is the best on the market for nowadays but I guess it's too pricey.
I found another option here at Thecrossfirestore , ABS plastic diffuser. The total is about the same.
I'll be happy if I'll find used high quality diffuser OEM Mopar or German fiberglass for my project.