While Jon's opinion is shared by many, there are and have been spring binding/pinchings in full size 1911's. The FSGR makes this impossible. IMO, I like taking any margin of error out of the equation. That being said, I understand that the FSGR's make field stripping more complicated, if you have a need for that.
My Springfield has a bushing. I push the spring, by the plug, and then rotate the bushing. It's only then you have to do the last step with inserting the 2nd piece of the GR and tighten with the allen key.