I got a 4" XD, I got mine before they offered the 5" in a stainless slide. I got mine within a year of the XD being released. I also think the instruction manual said not to shoot +p+ ammo.
The instruction manual in most pistols says to not shoot cast lead bullets or reloads either.
The Buffalo Bore round has been around a while and has been tested by the manufacturer in the Glock 19 and Browning HP, the former a 4" barrel and neither known for being overbuilt, without any notice of "Ruger only" like some of his .44 Magnum loads.
The XD 4" also comes in .40 S&W and .357 Sig as well and those pressures are not out of line with +p+.
Not directly pertinent but the .460 Rowland conversion for the XD .45 is a drop-in rechambered barrel with compensator and a heavier recoil spring, the gun otherwise remains the same and that is a fairly big pressure change/recoil impulse itself.
In any event, not being comfortable shooting a given type of factory-loaded ammunition is a personal choice, it doesn't impact what others might choose to do given their other calculations of risk. Particularly when the whole idea is that the "woods round" would be carried infrequently and probably shot less.
Anyway, we can probably call our discussion well-fleshed out and amiably concluded at this point if you like.
I don't want to sound all strident, in point of fact I spent the last year going over the "what to do for a woods gun" question myself. I trimmed down to .45 in the 1911 platform as my regular carry gun a while ago and would borrow my buddy's 629 for the field. I figured I should stick with what I know, since I barely get enough practice in with the carry guns (the "all the time" on stress training was hyperbole, more like "consistently infrequently"
).
So, I decided to go with always having a mag of .45 +P hardcast handy for "around town" and the .460 for real woods or knowing I'm going by salmon streams and such in town when the bears are out.