The aux fans should come on at 107 degrees. They are also triggered by high AC pressure regardless of coolant temp. The aux fans are really there to protect the AC compressor, not specifically for the purpose of engine cooling. For what it's worth, my 400E has always run between 90-100 degrees in summer with AC on. I think it's the nature of the beast -- a V8 stuffed into an engine bay designed for a straight-6. Everything I've read says that these engines are designed to run OK at any temp < 120.
If you are concerned, Water Wetter drops the coolant temp about 5 degrees.