Many would suggest the SureFire "Steve Ryan"
SRTH from LPS for your C3[-BK?]. It's an extremely compact, light-weight TurboHead Bezel that produces a narrow beam for longer range target illumination.
If you have a C3-HA, the best match is the KT2-HA. Based on the SRTH and KT TurboHeads I have, the KT doesn't produce quite as tight a beam with the N2 lamp. The KT TurboHeads are Pyrex and so heavier then the old Lexan lens versions. The KT's are still pretty compact though.
If you need a long range beam for duty use, the UltraStinger is one of your best bets according to many. It's longer and heavier but rechangeable.
I don't have an UltraStinger so I can't compare it to my SureFire TurboHead collection.
The price of SureFire TurboHeads has come down. They are dedicated to producing thin intense long range beams (Although the KT3 is a major disappointment compared to the Classic T3).
Remember that SureFire has four TurboHeads that will fit the C3 (KT, SRTH, "12PM" or T) and it can power one of three Lamp Assemblies (N2, MN15 or MN16) so you have many options and combinations. Also, your TurboHead and the appropriate lamp assembly can be used on any standard two cell body such as the G2Z, or even with a dedicated adapter, the 8NX/8AX.
Perhaps one of the reasons why there appears to be little TurboHead discussion is because few of us require such tools for our jobs. And by the very nature of the larger diameter reflector size, we find them difficult or inappropriate for general casual carry or use.
I personally use my M3T a lot. I find it to be very useful in the sub-rural environment that surrounds where I live. I also use models like the 10X and Classic 9NT fore longer range illumination.
Please check out past TurboHead topics on SIDB (Strategos International Discussion Board), and here on CPF concerning the SRTH.
Respectfully,
Al