Thank you for your responses.
I'm buying a new Springfield XDm, which comes with 2 mags. They are 19 rds pinned down to 10. I'd like to get more mags to it, but apparently even in the US the 10 rds are not available. They are selling the blocks which can be epoxied into the mag permanently to comply with California laws. I was thinking to do the same, but unfortunately it would make me a criminal here.....
Thanks again!