Thanx y'all; glad I mentioned it here.
I certainly wouldn't run a vol tanken on pure 111 but thought maybe a mix would provide a cleaner, more responsive effect without harm to the associated components, not that I was expecting to break into a 12 sec 1/4 mile with the juice. I suppose its safe just not to do it at all in the 500E...
But I have no problem throwing it in the other bastardized ride I got. The sooner the motor goes in the 16V the sooner I can put in that Stage 3 1.8T motor in it...but that's best left to the VW forum.
OK...end of thread.