Sorry for the late response. My initial preference was for the 6.8 but the dealer didn't have one on the lot, and couldn't acquire one fast enough as my patience had been depleted by my old 5.4.

I had brought my 5.4 in for service on a flat lifter (this was the second time), and at that point decided that I had enough of bad lifters, coil packs, and $1000+ spark plug changes. I simply told the dealer to keep the truck and put me in a diesel or 6.8.