Congrats on the new ride. I found the same thing when I got my new 2012 2500. I had all kinds of goodies from Banks installed and thought my 7.3 pulled good. When I got in this thing, it was like a whole new world. Just wait until you get to some real pulls! I have pulled some pretty good grades with my 9500# TT and at the end it was like the truck asked, "is that all you got?".
Did you use the tow/haul constantly while towing? Use of it may lower the tranny temps.
I had to change my mirrors, too. Found some off the net and they fit great, were easy to install and have held up well; for about 1/3 of the price quoted by the dealer.