I have used an original L2D as a bike light for a long time. The Quark Tactical, with its higher output and larger hotspot, is a clear upgrade path for the Fenix. I would rather use two Tacticals than a Turbo and Regular. The only real difference is that the Turbo has a smaller, more concentrated and brighter hotspot, and honestly I find the wider hotspot of the Tactical to be more useful.