I used to buy from intl-outdoor. They have a nice drop in that can be “customized” to your preferences.
http://www.intl-outdoor.com/xml-p60-dropin-module-alxm-p-656.html
Now I buy parts from fasttech and make them myself.
But yesterday I saw this thread.
I ordered two of the OP drop-ins from KD. Are they good? cant tell before I get them. They just arrived to the stores and as far as I know, Kaidomain and lightmalls are the only stores with XM-L2 drop-ins in stock at the moment…
I never use some thermal stuff around the drop-ins. But they should transfer heat a bit better if you do. Some 501B hosts have more room for drop-ins than others. So some would benefit more than others… There are several threads around when it comes to putting stuff around P60 drop-ins for better heat transfer…