Wowza lots of info, thanks all. Its not that I refuse to use 3m double back tape, its that that is what I used and it was centered when installed but the following day sun (I assume) it shifted down almost to the point it had shifted over the outside bottom edge of the recess.
I didn't want to mention it because the emblem I installed is a forum regular supplier but if it helps me get this fixed maybe the info will help. I got a pair, front and back, of the EVO R chrome Z emblem with black carbon fiber backing.
The reason I assumed OEM adhesive was different was because the original nissan emblem was held in place by a tar like substance the had rounded edges similar to when a tube of adhesive gets spread out then pressed between two solid flat surfaces.
also if need be I can get some pictures put together so everyone can see what I'm dealing with. Let me know, and again thanks for all the advice and help.
•edit- picture of issue...
Sorry if picture isn't clear enough from the angle but in eyesight you can see the overlap at the bottom where its sliding out of the recess and the top gap in the picture is between 3/8" and a 1/4" below where I originally set it. Very VERY noticeable in person, at least to me