Stage 2's will destroy a stock turbo. Or a van Turbo.

you can't just log on to guzzles site and buy a few o-rings for your turbo.
If you have damaged parts, they have to be replaced, and you have to know what is considered damaged, which I did not, and I'm going though problems right now. As well as setting seals properly, Apparently you need to fit the exhaust seal. Not 100% sure on that one yet.

Your better off just getting a new turbo replacement and sending in your old turbo's to the guy for core price replacements.

Your 7.3 should have 120-130 CC sticks in them already. My stage 1's are 160's. Stage 1's are about as much as you want behind stock turbo.
You probably have not done a wicked wheel upgrade either? Stock wheel on the super duties sucked. They replaced it with a junky one that has surge issues.

There isn't anything really to special about the van turbo. One guy in the OBS forum has done the swap. You get a different AR, and the super duty is already smaller than the OBS anyways at 1.00 AR, and the OBS is 1.1 AR. Faster spool, less boost, more heat. That van turbo will give you some EGT problems most likely.

Get to crazy on the injectors, and you'll have to start upgrading oil as well.