I know this topic has been beaten to death before in the past from some of the post I have researched, so I ask my brother who Owns a Big Truck (Peterbuilt); nothing but respect for those Owner Operator's.
I wanted to know where does Cummins put the EGT on his Truck, 600 Cummins Signature Series Diesel. It's Post Turbo.
However my brother also flys small planes and was a crop duster for a while.
He states that in Aircraft EGT's are used on the Exhust Manifold for each cylinder because you need to know of any problem immediately. So with that stated I would think that pre tubo will tell you of any engine problems quicker than post turbo.
My two cents...

27.5 day's and a wakeup!

USMC Al Asad, Al Anbar Provence Iraq