I didn't read all - but I had a similar fate so I thought I'd post up quick
cliff notes:
20G STi w/ 50-60k miles -
I had lots of blow by (a quart every 1-2 sessions)
Definitely detonated - it blew a hole through the piston (stock)
The octane of oil is like 2 - lots of blowby at high RPM/boost - ouch?
I had so much blowby the hoses all blew off/things caught fire etc
(don't mount your a/o separator anywhere near a turbo !)