I have the 'legal' version of UW, Overlord gave me a username. I find it a lot more useful than self destructing (in a betatest). I rarely use it. If I do, I ask the server for permission first.

About self destruct: I think you keep your hearts, they just appear as 5. For example, if you SD with one heart you respawn with one, it just appears as if there are 5. Same for instagib.

That's all I have to say.