Sounds interesting. Different, for sure.
I read what you posted about Rally Knight using modified 4EATs for rallying, behind a supercharged EJ series. (EJ25, right?)
That probably works fine because the SC makes boost down low, which means a stock torque converter can be used with great results. I would think it wouldn't work as well with a turbo since it probably wouldn't make boost as low, unless it was variable-vaned or the motor didn't rev very high.
Then again I've never driven a turbo automatic Subaru.