I need to make a correction & walk-things back.
My frame of reference is my XDm 5.25's in 9mm & 10mm (both have non-captive guide rods & springs as per TFLs post above), and my XDm-Elite 3.8 10mm, which has a captive & permanent guide rod/spring assembly.
So, my guesstimate is that the XDm-Elites 4.5 & 3.8 10mms have captive (double-spring at least for the 3.8) whereas the XDm 5.25 have single spring non-captive guide rods because the longer/heavier slides adequately soak up the 10mm recoil forces for proper function.
The shorter/lighter 4.5 & 3.8 need a different spring system to run properly so SA/HS Produkt went with that for those models.
Since there is a XDm-Elite 5.25 in 9mm I checked online to see if SA/HS Produkt went with a captive rod spring system for that larger/heavier model, and they did.
In this TFB review it shows the captive two-spring approach vs. the older/simpler non-captive XDm rod/spring system.
Leading into SHOT Show 2020, Springfield Armory has announced their New XD-M Elite series of handguns and we got our hands on one to tell you what it is all about.
www.thefirearmblog.com
So I see why some aftermarket vendors stated that their guide rods weren't for the XDm-Elite vs. the older XDm.
I wonder why they changed from the older/simpler non-captive XDm rod/spring system for this larger/heavier model when it seemed to work just fine.
So I stand corrected & learned something in this thread.