Ditto on the cam position sensor. There is a recall and Ford will replace it for free. I keep a spare in the glove box.
Change the fuel filter every other oil change. Oil changes at 7500 miles, it holds 4 gallons. I use Motorcraft filters. I also keep a spare filter behind the back seat just in case I get bad fuel, has not happened but I stay ready.
Shocks, I got from NAPA, probably not as good as the originals.
Brake pads, I got 120,000 miles out of the originals on the front, replaced with Motorcraft from Ford dealer and still on the second set.
It would probably help to give it a treatment of Diesel Kleen fuel additive right after the filter change. That may help with shutting off, can't hurt.
The engine oil actually fires the injectors, I know mine has more power immediately after an oil change. I use Rotella.
Do not turn up the power too much, the 7.3 can make plenty but the 4R100 transmission is not able to handle much over stock. Do change the fluid and filter, do not flush. Mine has a drain plug on the transmission pan.