:welcome:
Yes the KT1 TurboHead Kit for the C2 (6P/G2 etc) increases the intensity of the beam making an obvious difference.
But,
the N1 lamp has the same output as the P60 lamp used by the C2. As a result the beam is weak because although the beam allows light to be concentrated on targets further away, there's not really enough light to do this with.
It is my experience that 100 lumens (SureFire rating) is really the minimium to make the TurboHeads useful.
I would purchase a whole M3T but if you want to convert your C2 into a three-SF123A TurboHead model you'll need an A19 adapter to hold the third SF123A, and the KT2 kit.
If the KT2 kit is hard to come by you can get a KT1 and an MN15 lamp.
Note that the A19 only comes in Black, and that the KT TurboHead Kits come in Black (-BK) or natural Hard Anodised (-HA) so be careful when ordering to ensure you get the right ones.
Here's a C2-BK and KT1-BK along with an M3T-CB
I don't recall who took this photo of a 6P-GM (GunMetal) with A19 (BK) and KT2-HA
Shows want [fun] you can combine!
I hope this helps?
Al