I spoke to Subaru about this and the ECU 'flash' they offered which changed the parameters of fuelling and if the Prodrive version I had included those changes. The said they were included and from 2009 it was all sorted with the 330s model coming out.
Unfortunately that is not true as seen by quite a few failures (mine never had an issue - and it did get driven ). If what Subaru told you was true why is it predominantly No. 4 cylinder?
The Pistons themselves are not forged which deals with the ringland failure issue but a bespoke map for your motor is a strong recommendation, get the ECU setup exactly for your engine.
Petes mate had one fail through oil starvation so whilst Subaru state the failure due to high revs etc that does not explain the failure itself. Lack of oil for some reason would be a cause and it has been discussed a few times on the forum about how the oil will not return to the sump under continued hard cornering - Track use for instance) - so a baffle plate and uprated oil pump would be in order if that is how you plan to use the motor.
I really like the STI hatch I had and will have another, no doubt about it but I will be tweaking it to compensate for the Subaru manufacturing compromises