Based on the B-roll videos so far, I've noticed these two things
- The GT-Line Matte Grey in the B-roll had multi-reflector LED headlights rather than the double stacked projector headlights shown in Korea (e.g. the Yacht Blue)
- The grey GT-Line also used the red taillights as rear indicators rather than amber ones in the "hockey stick" that we've seen in all other videos.
- The door armrest panel in the GT-Line is black instead of white in the international version.
The 2nd one is disappointing since the taillights are rather thin. I'd imagine the amber ones would've been a larger area and perhaps more visible? (even if we don't get the sequential feature).
Side note, based on the videos from that Korean media closeup (I can't remember if it was Asian Petrolhead or another Korean media outlet), the 20" wheels on the GT-Line appear to have aerodynamic wheel covers; the 5-spoke design that we see isn't the actual alloy wheel design.
Edit: Added #3