I'm a G1 guy and I can't answer any G3 questions. I have, however, installed an EONON android unit in my Miata. Apparently the Chinese "double din" is close, but not exactly the same size as a real double din. I had to do a bit of surgery on the Metra install kit to get it to fit my dash. Measure this carefully!
Also I'm not overjoyed with the EONON unit for several reasons. I think the equivalent Pumpkin unit would be better.
Custom Turbocharger System
Genesis Charger and Discharger
NM license plate KERS
(Kinetic Energy Recovery System)
Scott's front and rear springs
GAZ rear shocks
2003 Lean Burn CVT (Wife's car)
2000 Citrus with aerodynamic extension
2002 Blue getting new engine