I think you should just leave it stock for the resale value. Also it's good as direct drive for me.
Just get a DX DIY host body for 18650, and you can tinker all you can with the same result or actually better. Using an 3x AMC chip regulator you can get 3 modes plus almost always 95% efficient regulation for an hour or so. Anything more like 4 chips 1.4amp driver will be almost like DD but with PWM dimming. The result is wasted charge from the cell, which means useless. If you want you can even add a TIR optic for the DIY host too or a good reflector.