I ran Mobil 1 Turbo Diesel Truck 5w40 when I first bought the truck, but 4X $23.00 is too much for me. So now I buy whatever properly rated 15w40 is on sale. I have 4 gallons of 10w30 for the upcoming winter change. It was hard to start with 15w40 this last winter.
Most of the truck forums strongly advise against extending OCI's in the 7.3 because the injection system uses the engine oil as a working fluid. Since that may be correct, synthetics can't be a good idea @ $90+ per 5K miles.
I have a Pure Power cleanable oil filter. It keeps the oil so clean that you can see through it even a month later. Taking is apart is a snap, clean it with Simple Green, blow dry, reassemble and install.
I expect to have the truck until I quit driving, because by all accounts the engine could go 500-700K miles. So, be vigilant with your fluids, and don't get too wound up with goosing the power. Then you will have a truck for about as long as you want.