If you feel that you 99 coach is in good repair, then go for the face lift.
Don't worry about the transmission heat. Ford did a good job of cooling, and heating when necessary, the transmission fluid.
The Banks Power Pack is a good investment. You'll like the results.
With you towing at the max, you may want to look at the rear frame extensions. Some of them are scary and could use some added metal and weld.
My graphics were old and tired. I elected to replace the old graphics with paint. Taping before the paint was long and tiring.
Richard