Blast from the past: emitter suggestions for a Jetbeam PA40?

It was one of my first lights as a budding flashaholic.

I don't recall ever seeing mention of the artifacts present in the XML-2 beam; a bright white hotspot surrounded by a greenish-yellow corona with purple spill. For a long time I didn't care but, after experience with modern, warm and high-CRI emitters, I've begun to care.

This will be my first foray into modding. I've not seen mention of the PA40 being modded, and I'm not sure the red ring holding the head assy. is easily unscrewed.

Two questions:

1) Does anyone have experience and advice on disassembling the head for emitter swaps?

2) What emitters would be good candidates for the PA40 that are likely to satisfy my now-spoiled eye.

Thanks all!