I have the first two they ever made, and yes I sent the factory one in so they could use the factory spring. The advantages is the cycling is so much smoother, the back plate that buts up against the barrel is not some slim, flimsy piece of metal this is all cnc parts. So there will be no failures of the gun randomly stuck open (reason why both of my first gen shields had replacement guide rods they both failed.)

Trust me when you feel the cycle action in comparison to the factory guide rod it is night and day difference.