I own a 2003 with 92k and the 4.6 and having read and re read all the procedures from here and on the RAVE I swoped the coolant for green 50/50 and replaced my thermostat. before doing the swop my Ultra gauge showed the temp on the highway at 203 and would peak some times to 217 when in traffic.
On taking out the thermostat it was date stamped as 2003 so was obvious the original one and needed to be replaced. I did a coolant flush and then 2 other flushes alll the whilst doing the proper bleeding to get the air out.
Now the ultra gauge shows 195.8 down the road and in traffic 199-201.