I too have asked this question without much response. There are a couple of guys on here and other gm forums that have used these exact spacers and had zero issues. I called ECGS and spoke to tech support about the same concerns you have and in a nut shell as long as the shop installs it correctly you should have nothing to worry about. They told me they have sold hundreds of these kits and have not had 1 truck back in for issues. He did however clarify that it isn't the most ideal way to do a gear swap but for us guys with 3.08 rear ends, we have no other options. The techs opinion was that as long as you're not running crazy HP numbers and your not doing neutral drops, the spacer can be trusted. He said the factory G80 is more likely to fail than the ring spacer. I plan on swapping to 4.10 by years end and I'll have to use the spacer... I'll keep ya posted