Received my Deep Turbo C Heads today. My initial impression is not as positive as nailbender's and LuxLuthor's.
None of the SureFire Classic incandescent lamp assemblies I tried fit properly. I tried 4 P60s, 1 R60, 1 R30, and 1 P61. They all hang up before the top lip of the LA gets flush with the bottom of the Deep Turbo C reflector. I'd estimate that there is a gap of about 2mm. The head also doesn't screw down all the way on my SF 6P host and there is a large gap of about 3mm. Since the product was advertised to work with stock P90/91 lamp assemblies, I consider this to be a major fault.
In addition, the reflectors each seem to have 4 or so little defects in the deposit, where it looks like the reflector material was deposited over some small particles that got onto the surface.
I tried 3 different P60 LED drop-ins, and got mixed results. All of the LED drop-ins fit flush, so at least that was encouraging. But I got no increase in hot spot lux (throw) for a DX6090 and a DX11836. I got about 5% increase for an OpticsHQ drop-in, but the beam quality degraded signficantly (noticeable ringiness).
For completeness, I tested a Malkoff M30. It fit fine, but again I measured no difference in hot spot lux.
My moddoo triple XP-E drop-ins aren't finished yet, but I test fitted the aluminum heat sink and that also fits flush in the Deep Turbo C Head. Since these drop-ins use an optic (as with the M30), I don't expect much (if any) increase in throw from the Deep Turbo C Head.