It’s funny how as enthusiasts, we often respectfully disagree. Having used both the acrylic and glass platters on a P25 I would much rather have the glass. Leading edges are more defined, or to put it another way, harder. It is a matter of preference. I have not tried the POM platters though.
I sold my Technoweight, finding that it certainly changed the sound of the arm. Again, preference comes in, but I prefer the tungsten Rega counterweight, though I can certainly see how some will prefer the Michell.
I never had any luck with the stock Denon 103 and 103R in the Rega arm, finding them rather washed out dynamically. Zu uses the Rega arm as a design center for their modified Denons and adds quite a bit of mass to improve SQ. My preference is a very heavy arm for the 103. On the cheap, an Audio Technica ATP12t, with a bit more money maybe a Fidelity Research or Thomas Schick.