There are a lot of theories regarding the heavier springs. Some say they help to reduce some of the snappiness in the recoil. Some say a heavier spring is better for shooting heavier loads, and a lighter spring is better for lighter loads. Is there truth in any of that? Probably to some degree.

Even if one gains nothing, the frame of the gun should not become damaged from it. If the guide rod and/or spring is what caused this, this is the first gun I've had pieces of the frame break right off from it, and the first gun that I've ever HEARD of that happening. It's something S&W might want to look at.

Keep in mind also, we are all just assuming that the guide rod and spring are the cause of the problem. We have 3 examples of this problem in this thread and all 3 happen to have a Galloway guide rod. The Galloway guide rod is a fairly common modification for the SD40VE, so one would imagine that this would be a more common issue. Perhaps there are people who have this issue who left the gun in the factory configuration. It doesn't seem like there are many of these guns out there with a high round count yet, so maybe by the time they get to 3,000+ with the factory rod and spring, we might be seeing this problem more often, and the stainless rod merely hastened it. They are not sturdy tabs by any means, and I would have to imagine that at some point, they are going to break off regardless of what guide rod someone is using, simply from normal wear.