I did not build my GTM originally, so I can't say I know your pain exactly as you are experiencing it, but I have damn near rebuilt everything on mine now with all I have done. And mine is now in the paint and body shop undergoing a complete new paint job (with a few select body mods being incorporated along with it this go round). Anyway, you must be very close. It has got to be harder the nearer you get to the finish line. To see the light at the end of the tunnel and then be set back on the small little details is totally infuriating, I know this from pretty much ALL the car projects I have ever worked on. In the end, you will at one point say that all the pain and effort was worth it. Because by that time, the BS will all be in the past and you will have nothing but enjoyable GTM ownership experience going forward at that point. Good luck, man!
Oh, and beeman- if Mostafa doesnt want/ need those gen 1 headlights, put me on the list of recipients that would gladly take them off your hands.