My 500E normally runs about 90, but can run up higher if I'm pushing it hard. I've seen it hit about 110.
You mentioned tuning might have an effect on temp and I'm curious about this. I know that with my older cars, a few degrees retard could make a big drop in temp (especially if the timing was advanced to the point of detonation. Also a slightly richer fuel mixture helped bring temp. down. In this case would a performance chip help?
Benzmac and others what do you say? Inquiring minds want to know!