The spacer size depends on what you use on your pistol already. There is a small, medium, and large size.What mags do i need for my xdm i need thr ones that hold 13 and are they the same for xd and xdm, next what magazine grip spacers do I need I saw some on cheaper than dirt for $27 and all it said was xd compact
When it comes to the .45 the XD and XDm mags are the same. Not so with the other calibers. If this is with the compact grip I recommend carrying with the 9-rounder. The spacers aren't required on the 13-rounders. The x-tensions are there strictly for continuity. It's perfectly fine to use the 13-round mags as they are. Looks funny, but works.
I talk about the 3.8 here: (start at 3:07)
Thanks for the info.