John,
I just mounted my EGT probe this weekend. I put it in the manifold, just before the turbo. I think this is the most accurate place to monitor the EGT from because this is where it is the hottest. Sure, it is a lot more work to mount it here (removal of turbo, etc. ) but this is the best place to keep an eye on your EGT. Just be sure to use a vacuum cleaner to suck out all of the metal shavings when you drill your hole in the manifold... the turbo doesn't like metal shavings. FYI, your EGT's in the exhaust elbow after the turbo will be roughly 300-375 degrees cooler that in the manifold.
Hope this helps!!!
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Evan A. Beck
98. 5 2500, 4x2, RC, ISB, A/T, Forest Green/Driftwood, 38,000 miles
4" Exhaust, Jacobs E-Brake, K&N Filter, Auto-Meter Ultra Lite boost & pyro, turbo silencer ring removed, plus many other cosmetic modifications