Just wanted to share my success with a led swap i did to my nitecore ea4. After swapping out the old xml to a new 20mm noctigon copper star with a xpl v6 2c the results are as follows- old xml 22000cd, 40 lux ceiling bounce, new xpl 30000cd and 52 lux ceiling bounce. Just as a comparison against a fenix tk 75 at 1200 lumens ceiling bounce lux 57[ ea4 52 lux]]. This is a great gain and est at least 1050 otf or about 30% gain. As some of my lights are older xml or xpg i now look at all of them as needing an upgrade and these new gen crees dtp on copper really deliver for a minimal outlay. I got the v2 stars from ios [Hank] and delivered in under 2weeks to Australia, very happy. Also i really like the xpg2 s2 1d which i dedomed which has a great tint[not green] which turned my sunwayman t20cs into a 55000cd throw monster. If i can work out how to post pics i will share.
How did you get the EA4 opened up?
Remove bezel, lense, reflector, delrin ring and battery cap, now to remove the driver, u need a push the driver and heat sink [ press fit] from battery end with a thin wooden dowel rod , tapping softly with a small hammer, positioning dowel between the - spring and + terminal on both sides carefully , then the whole light is now disassembled. The problem i ran into was the thickness of the original aluminium pcb which is 1mm and the noctigon is 1.6mm which is critical - so i removed .6mm off the base of the reflector so the bezel can screw on and not hang out. The led pcb is not screwed down and is held down and tensioned by the reflector bezel tightness and centred with a delrin ring. One thing i noticed with the v2 noctigons ,the terminals pads are further towards the outer edge allowing good clearance , v1 does not have enough clearance on the ea4.
i thought it was glued shut with very strong adhesive, it looks like you got lucky 
The bezel came off easy, no loctite at all and removed by placing it it on a rubber mat and twisting. This is a 12-2012 model and has worked flawlessly, but i dedomed the original led which tint shifted to toxic green which i didnt like and thought i would leave the dome on this time. Another test against my jetbeam bc 40, 26000cd 38lux ceiling- ea4 30000cd 52lux. The ea4 is now much brighter than the bc40 where they used to be pretty even.