Alot of argument eiter way.
First I'll say my pyro is post turbo. There is a spot on the exhaust elbow intended for probe installation. In that location, you measure temp from all cyl's, but temps read lower and slower than at manifold. Also, there is about a . 5 in a billion chance the probe can break off and kill the turbo if its installed in the manifold. It is rare but can and does happen, and I have poor luck if any at all, so I figured i'd be that one chance failure and went with post turbo.
Pre turbo mounts show change in temp a little faster, and indicate a truer value of how hot the gas is leaving the cyl's. Problem is youve got a split manifold ( mine does, anyway) and would be reading either 1 2 3cyl's or 4 5 6 cyl's. Given the choice, I choose the 4 5 6 location, as the rear cyl's typically run a little warmer. But, you could have probs on the front half of the engine and not know untill its to late.
Seems like a lot of if, and, & but. I'll play the safe card and vote for post turbo.