G'day Kramer,

There is another way to look at this Turbo/Exhaust/EGTs.
I done a lot of research into exactly what your proposing to do and found the following.

A lot of the state side fellas take the practical view that it is not the 3" OEM piping that is the problem causing high EGTs under load, it is the staggered & baffled OEM Muffler box. Simply straight piping it (I believe you've done that) or lopping out the staggered OEM box and fitting in a straight through muffler (they call it the BTM Mod (Big Truck Muffler)) is sufficient enough of a fix. And a hell of a lot less expense and stuffin' around.
The point is that the Turbine outlet is 2 1/2" and the increase in the bore of the OEM downpipe is more than enough to get the gasses away. It's when it hits the staggered and baffled box that the build up commences. Add that to the extra length of the tail pipe and those addition frictional forces only add to the problem.
My understanding is that a 'Normally Aspirated' (non turbo) diesel won't operate efficiently without a muffler to supply the back pressure needed for low down torque/grunt. However it is this action of squeezing (if you like) of the exhaust gasses out of the turbo outlet that supplies the back pressure on turbo diesels.
So unless you want to drag race ya 7.3, then big bore piping is not going to give a lot in my view.
I tracked down the closest straight through muffler to the BTM they use in states I could find here in Aust, lopped out the OEM box and ditched the tail pipe and dumped it out just in front of the rear tyre.
My GCM is almost never less than 7T and I pull in all terrain and haven't had a EGT problem at all.
Just another take on this for ya mate.

Cheers,
Reg
"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery."<O</O
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