Mine was already tapped for egt/dp right at the flange (3 pc. a.m.) on the exh. manifold. I wouldn't really think it'd matter exactly where as long as it's near the flange...I went on edge's site to see where they have their egt sugg. since bd's wants theirs after the turbo...
Anyway, next to your egt probe wouldn't hurt either. All that matters is the reading comes from the manifold.