Old thread.. But i needed to post for people searching for this like me who couldn't find a definitive answer.
I ordered both the Metra and the Scosche and found the Metra to be better color match to the original plastics and looks nicer, but has a larger opening and requires the use of a trim ring that is included. The double din sits more inward/regressed into the dash than on the Scosche.
The Scosche is a better fit in terms that the opening is not as big and fits double dins precisely (doesn’t require trim ring), but the plastics are a glossy black color that don’t match the rest of the car and looks cheap. The double din sits flush with the front face of the kit.
See pictures in album:
Nissan 370Z Forum - Bandit_Kaine's Album: Metra vs Scosche dash kit