Hmm i dont think they are any point to argue with them, i am pretty sure that the car have done some ing. knock. Maybe a better brand piston could survy a little longer but i doubt.
But i temp to try CP pistons
Saint: Almost same spec, i have some news mods. I am going to have dual fuel rail, on my kappa manifold. (take som pic when it is done., then i would like to have a EGT, and a MSD knock alert.

I am going to take some pic of the rebuilding, when i start.