I have tuned quite a few 650+ hp LMLs and around 1500+ LMLs i have tuned overall... I have not heard of anyone cracking pistons on them yet. My personal LML is running around 750+hp with 2600uS and 28* (its on borrowed time i know) and is still playing nice. Obviously, it is all a time bomb when we increase power.
H&S tunes are around 1400uS on hot with 18.9* of timing.... I would be willing to say either the following:
A.) Defective from factory
B.) Major abuse while running hot tuning
I am excited to see more and more LMLs modded and everyone TRULY push the limits. All i can speak from is my personal experience with them and my thoughts. Hope this adds a little!
Kory