I recall reading in a magazine that Saab tested a LSD on the FWD Vigen
(a high horsepower turbo engine). It increased torque steer to an
unaccaptable level and they never used it (this was an anecdote in
some car magazine that tested it). I guess they concluded it was better
to just let the tires spin (AWD must have been out of the question).

Have you been able to find anyone who added LSD to their T5? It would
be interesting to hear any first-hand comments about added torque steer.