Sounds to me like you need to take it to a reputable workshop and get it checked out...

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No Subarus currently owned

Dcd will not affect this

DCCD turned on lock can cause vibrations in driveline when turning at low speeds, but I am pretty sure with no controller your dccd is as unocked as it can be.

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2001 Liberty B4
12.7 @ 178kph 1/4 mile
59.1 Short Track @ barbagallo (Federal 595s)
58.2 Short Track @ barbagallo (Toyo R888s)

Okay thanks for that info. The other thing that I am most confident that it might be, is the clutch packs in the LSD diff, it would make sense.