Help needed please

What is the best single mode drop in led or led that can be used in my wf-501b style flashlight, I already have an Aspheric lens and black reflector spacer.
Ive been looking on eBay and there's lots of different ones to choose from so that why I'm asking for help please as i want my flashlight to be as powerful as possible.
here are a few that i have seen on eBay, which one is the best.

XML-2 R5
6V High Pressure Xenon For Surefire P60 and Ultrafire
7.4V Xenon 1Mode 130 Lumens For Ultrafire
Cree XP-G R5 For Ultrafire
Cree XR-E For Ultrafire

Thanks
Welsh-Rhino88

You know the real reason to get a "P60 Led insert" (the one that fits into these bodies) is to get the tint one likes
(as well as number of Levels, led model, Output as well ... OK)

go to member nailbender's shop (WWW dot cutomlites dot com) and purchase one
"P60 style replacement module"
P60 XPL domeless, smooth reflector, one level, coolwhite or neutral 3C ...
single mode in Your case
(even when the typical 3-mode is the best compromise, imho)

You might ask for custom higher power (for less runtime)
carefully mount the insert with added copper tape then (which You get together with the insert) to pass the heat to the Body as quickly as possible


PS: for the last years I also used bodies like You mention (+ nailbenders inserts) as lights when my buddies asked for, but now totally switched to the Solarforce Hosts that are also offered at customlites.
There simply were constant Problems with the cheapo crappies - mainly bad contacts and thus less Output.
The Solarforce Hosts cost just a tad more but work much better.

... later You can Switch to even better 1*18650 host and enter a new insert when the "Need" arises
like 18650 modded SF 6Ps (oveready), or bodies from Fivemega, or ...