I've been checking various sites online. It seems the #78 GT2 model is only available in Europe. This might explain why Tischer can't get it.
Has anyone been able to get it from a US BMW dealer?
2011.5 M3 Coupe: Space Gray, 4MY, ZCP, ZCV, ZP2, 494, 5AC, 655, and 752
Mods: Full Venture Shield protection kit, RPi scoops, Euro fog light switch, LUX 3.0, clear reflectors, OEM black chrome grilles and side gills