4D Xenon Mag gunmetal - What should I do?

I picked this light up at Walmart for $17 today. Looked too pretty to leave it there by itself………

So other than converting some 2AA mini-mags to led, I have no experience with doing mag mods.

Considering the fact that I can stuff a boatload of eneloops or a bunch of 26650/32650 cells in this light, I want to make something impressive.

Either a hard driven XML2 or an MT-G2. I have seen the various drop ins sold at FT, KD, or DX……not sure if those would give me what I desire……

I just don’t know where to start. I also want to keep it from being too expensive. A lot of the mods I had searched are getting old and I am wondering if there is a current “best mod” so to speak.