Spoke with one of the technical staff at Monacor - Sweden. The tweeter is identical. I don't know if its an oem production or if they are retailers but it is indeed the same drivers =)Note: Just in case someone is interested. 2 drivers ( cant remember wich ones ) are altered from the original design from motorola.
I also learned that retailers of motorola piezotweeters usually rename the product to fit their own purpose, hence the same drivers have lots of different names.
So for all you Swedes wanting to build 1 Pi or 2 Pi:s check with www.monacor.se for the KSN-1038.
Regards // Mattias S - Sweden