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 V4, clear reflectors, OEM black chrome grilles and side gills, black hood vents, IND F10 M5 shift knob and boot