I've been using Motul RBF600 as a top up in mine for some time now... Including two track days..
No problems what so ever.. Beside the fact that the clutch is on its way out, due to the extra load, turbo :)
Eventually, when I get around to it, they recommend sucking out the fluid and replacing, doing that a couple of times so you get it all replaced, without have to re-blead the system which is a PITA!