Plate and stabs are stock (so screw in stabs, and PC plate).
The stabs are the least rattly that I’ve had so far (although my daily driver for the last few years no stabs, as it didn’t have any keys over 2U).
I’ve had acrylic, and stainless plates on my prior custom builds, and my Ergodox has aluminum plates, and I’m quite happy with the poly carbonate. At some point (when they come back in stock) I’ll probably get an aluminum plate just to check it out, and will grab the Pro => Max sound kit as well.
I’m using the K Pro Banana switches. I’ve run Gateron Browns primarily, but I my Erogodox has the V2 Zealios, and another build has R6 Zealios. The Zealios were a bit heavy for me for all day typing, but I like the banana switches.
I’m using the stock caps for now as well. I’m not entirely sure I love them, but I figured I’d give them some time before switching to a GMK or DSA set.