FWIW, I had a friend who owned one of the first AR's in the A4 config that I'd ever personally seen. He's a high power shooter, and had seen the handwriting on the wall, so he was quick to convert from his M1A to the -15. He is a lefty, so he had made mods to the receiver so that he could rack the bolt from the left (a swiss cheese receiver!) Of course, he had all the other High power goodies (scope, aperture sights, etc)
The rifle as is would shoot 1 inch groups all day at 100 yards - plenty good for high power matches. But being the perfectionist, he wanted better. So away to the Cryo guys he sent his piece. When it came back, he had to work up a different load for it, using the then new 80 some odd grain VLD's that he would eventually use.
The bottom line is that he was able to shrink his groups almost by half. Even I could manage an inch and change at 200 looking through his scope.
So, here's at least one anecdote where the cryo stress relief was beneficial. I think that if this is to work correctly, you have to make a total commitment to getting the best out of your weapon. One cannot approach it like the wanna be street racer who drops a 500 cubic inch screamer into the front of a rusted out Nova, and expects to dust everybody. This process will most like work best for the benchrest shooter, or high power shooter who expects the absolute best accuracy from his equipment - and is willing to invest the time and money to tune it to those levels. Anyway, it's food for thought!
Good luck