I have read the threads and asked a modder about my KL5 and the consensus is that they are VERY difficult to open, they are not like the KL6.
I mod many lights and I passed on getting one and doing it.
I am willing to have you mail it to me and I can see what I can do, I have a lathe to make a sink. What battery voltage are you wanting to use? What led?
My time is limited and I don't like pressure, however, I do get it done because it stresses me out knowing I need to get it done, I like it to be fun.
I have a very custom KL6 with a 3amp 3 mode and copper and aluminum heat sink. Another with an MCE warm led and stock driver. Very bright, gets warm. But the KL6 and KL5 are totally different behind the reflector.
If you are wanting to talk, I would rather use the phone, PM me and give me a number and time zone.