do you have a pic?
what i now understand is the second combustion rig land is the one that let go not actually the top land? would that stmt be correct? i had assumed it was the top land that had let go and that by moving the land up closer to the chamber it was going to excite the problem even more. however if its the second land that is causing the failure i can see what u mean as the 2 combustion ring land is half the thickness. that would be fixed (or better off) with newer pistons as they are much thicker in that area....
but this still sounds like a tuning issue more then anything (detonation) what was the air/fuel ratio? also you might want ti try a cooler thermostat if you havent already done so (seeing as i dont know all your mods)
in the mean time while we are still working this out.... all turbo owners might want to keep the boost low and the mixture rich just to be safe
