Good evening and Happy Election Day! I hope it proves to be a good outcome for the gun community. I apologize a thousand times over if this is a question that has been asked to death, but I am not lazy. I did a forum search and did not find these questions posted earlier. If I missed them, then shame on me. I have a Gen4 G22 and a Gen1 G27. I would like to add a Gen4 G23 to round out the .40 collection. I am intrigued by conversion barrels that will allow me to convert these into 9mm's. I fully plan to use 9mm magazines when using the conversion barrels. Here are my questions: Will I need to buy different guide rods and recoil springs for the Gen4's? If so, do they need to be specifically designed for the conversion, or will Gen3 9mm guide rods and springs work? Since the .357SIG is essentially a 9mm projectile in a necked down .40 case, will a combination of a .40-to-9 conversion barrel and a .40 magazine allow me to shoot .357SIG or are there other factors that keep this from happening? Thanks in advance for your replies.