About 20kg, from memory. Hang on, I’ll try and find out for sure.
edit. Struggling for an exact answer. My FD ones are 2lb lighter than standard and I’m pretty sure they weighted in at about 22kg when I checked them in for the flight home from Vegas. They certainly felt about that weight. How accurate do you need?
Felonious Crud I'm intrigued on your FD discs, having called FD (as well as their UK supplier) who confirmed they only use OEM discs from Maserati i.e. they don't make their own.
These are the ones I’ve got. Cross-drilled and slotted, and definitely different from the OEM ones they replaced!