DMP = Top 1% in terms of revenue of DMs (spent on CX/KA metal only, believed to be the region of ~150-200k USD a couple of years ago, perhaps Optm can confirm this for us?), with additional benefits over those of DMs with the most significant being DM card for spouse
IN = Invitation only, has no correlation to BIS miles or revenue, enjoys DM benefits
I've seen two DMPs so far. While I've not seen the DMP card/tag in person, I've heard that on the lettering on the left hand side (where it usually says DIAMOND DIAMOND DIAMOND) that they have a rainbow shine on them instead of the "regular" shine.