K20a Engine failure

Hi guy's i run a k20 turbo charged Honda Civic FD2 type R 840whp successfully from more then year and few days back i had an engine failure i am attaching the datalog and pictures of the blown engine to find out what went wrong because my engine builder and my tuner are both very competent guys and got a mixed reviews .I do not want to blame anybody i just want to be safe for next time .

What was the expected service interval? How many hours / passes / km did you get? What was the maximum RPM during that time, and how much time near the max RPM did the engine experience?

I imagine an engine with 420 hp/liter is expected to be torn down completely fairly regularly, and particularly if it has experienced overrevs or any knock events under boost.