With a fully charged 18650 you will have reduced output, you need 2 li-ions as Pi said.
Take a look at DTR's test thread. According to the results an m140 at 1W has an operating potential difference of 4.2v.
However, in a not so perfect and inefficient reality you will most likely see something closer to 400mW with a single Li-ion.
The X-drive is a buck driver you would need a higher voltage than what the diode will use so the driver could buck the voltage. You want to get a X-boost driver for that build unless you do as PI stated, however you'll have reduced runtimes... could get quality cells to help out I guess.
Hi Lazer God ( love the name). I'm completely new at building. Still at the solder a kit together stage.
But one of my kits used a M-140, driver set to 1.8. I use two 16340 batteries, and it really kicks ass. Over 2 watts using G2 lens on my LPM. Sometimes I switch to a 3 element lens just to change the divergence to something cleaner. Get a needle like beam too.