Kind of odd. As Rob said, I made 462whp on a stock 9.5:1 JDM motor (just cams, stock heads, studs, gasket, etc), C16, a JWT ECU (3 bar/72lb/Cobra MAF) and the only tuning I did was advance the timing to 20* to take advantage of the C16. The car has made it through the LA convention, where it ran all day long at Streets of Willow Springs (6 or 7 20 minute sessions at full tilt), then went and ran low 12s on street tires (120-ish mph at a crap track with strong headwinds), then drove home to San Diego, all without a trailer. I've also run the car in multiple time trial events (once again, 20 minutes straight at full tilt, either flooring it or jamming on the brakes) in 100* weather, and nothing's ever happened to the motor. Racing a Supra 3 times in a row is nothing compared to the abuse of a road course. I've even ran the pump dry a couple of times at WOT on the track (forgot to check fuel before going out) and still nothing. That motor's still ticking after 20k+ miles of abuse.
How did the plugs look? Was the headgasket eaten away? Evidence of pinging in the other CCs? Unless that thing's tune was really off, it should've given some evidence that **** wasn't right before it finally let go. I haven't read the whole thread, but did the car have a wideband on it? EGT? Datalogging?
The only time I've holed a piston on that tune was when I accidentally turned the boost controller all the way up (over 30psi of boost, no clue exactly how much since my gauge only reads 30) and it still lasted nearly an entire 1/4 run on stock pistons.