How post-cylinder EGT relates to pre-turbo EGT

[Mk3ukr]

Hello all
Great forum, I read and learn a lot rom here since I purchased my Aquamist 1s system 4 years ago. My question is not exactly WI related, but I hope to get comments from knowledgable guys.
Recently we had discusiion about correct placement of EGT sensor. Some people install it in one of the cylinders runners, I always installed mine pre-turbo. My opinion is pre turbo EGT is higher than post-cylinder, I don't know for how much, possibly 50-70C higher. I think it depends on how big restriction gas side housing represents. My collegue who drives heavily modified WRX argued he never saw more than 800C from stock pre-turbo EGT sensor and regularly see close to 900C on his Greddy gauge (sensor tapped into the one of the runners
I work as marine engineer and know from experience that it is very common to see on diesel engines cylinder temperatures let's say 430C (we have thermometers on every cylinder), pre-turbo ~510-520C, post-turbo ~430C. I know when hot gases collide entering the turbo their teperature goes up.
I believe the same laws of physics can be applied to automotive turbochargers. Or am I missing something?
Thanks