Anytime you trade a Glock for a S&W you do well. Changing the rebound spring should lighten the action a bit but might slow the trigger return (probably not an issue w/ a gun that's not used for defense). While you're inside you might lightly hit the rough spots inside w/ a fine stone (stay away from the sear). Smoothing out the tool marks cuts the friction & makes it lighter & much better. I prefer Altamont grips.