Keep the 3. 54's, add gauges (pyro, boost and trans. temp) and invest in DTT's tc and vb and throw in a box like EZ. These are basic upgrades that the truck should have come with in the beginning and will really bring the truck alive. I am pulling 600lbs. over GCWR of 16,000lb and it makes all the difference. Before these additions the truck would change down to 3rd when climbing a slight hill. now it accelerates going up the same hill without changing down!!
FWIW a friend of mine has the same configured truck, bone stock and pulling a 12,000lb trailer and he manages okay but complains the truck is low in power!
Just my 2 cents worth.
Richard