Adding a SureFire A19 to your C3 and a TurboHead (such as the KT2) gives you a four-SF123A TurboHead light. This requires the MN60 or MN61 Lamp Assemblies (not the N2 that comes stock with the KT2 for three-SF123A models).
I understand there are aftermarket "tube extenders" that can be used instead of an A19.