I think the fuel system is the least of your worries. The 3126b HEUI pump is a much, much bigger concern and when it fails (not if), you will be replacing the fuel transfer pump on the back of it (really simple plunger pump run by an eccentric skateboard bearing on the HEUI), and you may be replacing the injectors as well since often a HEUI failure results in them being contaminated.
At which point you have spent a bunch of money on fuel additives that resulted in no benefit at all.
The 3126 and C7 are both designed for ULSD and as such have no requirement for additional lubrication. In our engines this is purely snake oil and wallet flushing. And having injectors that last 1,000,000 miles but have to be swapped at 150,000 miles (or sooner) due to a HEUI pump failure really makes zero sense.
Get the IFS filter kit to protect the injectors. Pull the oil cooler and have it decked 0.020" and get the updated gaskets for it. Get a bypass oil filtration system. Run high quality synthetic oil. Change it every 5,000 miles. Cross fingers.
I've now been party to two 3126b HEUI failures and on this last one (literally last week) I got to keep the HEUI pump off the engine and disassembled it. Not impressed to say the least. The pistons are TINY and the cylinders are brass. It's no wonder they don't suffer dirty oil.