Has anyone seen a gtir crank snap yet? You can grind one down to .50mm under size ,due to the fact the crank runs on a film of oil and is so big to start with I doubt you would ever break one . As for cracks on the journals, get them x-rayed I bet it's just the gas nitrided surface layer that has craze marks......... And as for how much power a ground crank will handle 00sid ( fusion white drag gtir) was running 500 on a ground crank for 20,000miles, jamaican gtir 850 bhp and mazworxs run 1400bhp plus on a gtir crank.