Hi All,
I took my blitzen into the Armstrong Subaru in Chch, and the service centre was able to download the software from my ECU, send to Japan then reload software more accurately configured for our fuel.
The car seems massively smoother, haven't heard any detonation as yet (it was BAD before this). I dont know if it's necessarily making any more power, but the power is not being sapped away by the ecu trying to compensate for the detonation.
This was an awesome bang for buck improvement, as the software + labour (including road test) came in at around $145 (can't guarantee it will be this cheap for you - road test duration can be impacted by traffic etc).
Will report back on any improvements to mileage - only had the work done on Tuesday.
Anyone else had this done?