I had mine done by my trusted Subaru dealership shop. I was given the option of going with Redline synthetic ATF at a higher cost & I decided to do this on my '03X & my '07 FSXT. I also went with Redline synthetic in the front & rear differential. :smile:
The Subaru HP is the best IMHO. Subaru has indicated tat Dexron III is not good for the Newer Subaru, long term. That tells me it should be better in older Subaru's than ATF's which only meet the Dexron III spec.