Vinh is great to deal with and does excellent innovative work on more branded type lights(fenix/thrunite/acebeam etc etc). There is james3 in the UK who also does mods, like convoys and .............well quite a few options if you send him your light and what you want.
There are a few modders about, for the latest releases and monster lights vinh at skylumen would be the choice. For p60 triples you again have vinh and tana along with adventuresport to name just 3 .
So depending on what you want, will depend on recommendations.............and budgets
If you are getting started, dedicated thrower, dedicated flooder, maybe a do it all type of light. Pop can light along with other compact lights like the m43. Then different single 18650 lights, 26650 lights, dual cell(2x18650) and 4x 18650 types(back to bigger lights, dedicated/flood etc). Then back to the p60's, single,triple,quads all in your choice of LED . colour temp(4000k,5000k,6000k etc etc) and drivers. Then host options(empty flashlight) from custom, to surefire to cheaper solarforce options................almost endless!!!
Right now the tn42vn would be my choice of dedicated thrower.
For a flood light, the tk75vnQ70 is still hard to beat for output/heat dissipation and flexibility (run time kits).
You have then the xhp 35 HI choices, tn40vn which is 500kcd and 9000lm, bigger brother x65vn at 10,500lm and 620kcd.
Still the rc40vn and x65vn have some great options now and coming, crazy ones with xhp70's and maybe other options down the line. These are limited and not cheap with 2months + build time(bit each day, here and there type as demanding). But expect $1500+ and a wait, in return you will get one of a handful of custom made , highest LED output lights available.
My choice right now would probably start with what i would get most use out of, then go from there. Try not to buy too many cool whites and experiment a little with colour temps. 5000k is a safe bet, still cool side of neutral yet benefits of good colour representation without any noticeable lumen loss to the eye(5-10% generally).
Hang out in the lounge for general chat and questions
EDC( so every day carry) tend to be the most used day to day, of course check v54 options. Custom or semi custom there are many options for that extra special light. Not always the highest output, check HDS rotary/clicky out. Check McCigzmo's out,tain and other options including sinner................etc etc etc.
Thats just scratching the surface and quick off the top of my head, could go on and on and............
Enough waffle from me