I just finished this today and I am very happy with the results.
What this mod entails is turning your glow plugs off while cranking your engine. I couldn't find this anywhere on the org so I thought I'd throw it up. The following link takes you to the write up page:
Dzl Jim credits The Tank for this mod; also on this page are instructions for bypassing your glow plugs with a temperature sensor when your truck is toasty warm when starting. It seems like a great idea, however I have a bypass coolant filter system and the filter head would be the only place to mount the sensor. I took temp readings and even when the engine is still warm the filter head has cooled down enough to make the temp switch useless for my application.
Now this writeup is on an OBS truck but the same applies for the 7.3l Superduty's. The only difference is running the starter signal wire from the starter itself up to the relay. I mounted my relay on the GPR itself, not on the fender.
I let my rig sit untouched till tonight to see the results. It turns over much faster now and fires right up from dead cold. Hope you guys enjoy it.