thats a lot of metal.
pff09...the doo-dad on the left side is a thumbrest. helps with location, helps steady under recoil, helps in pointing, but limits the classification you can run this pistol within during certain comps. Also looks like an oversize safety/decoker as well as a large magazine release. I'm sure you know what the magazine well on the bottom is and its function, but if not, it opens up the bottom of the magazine slot for quicker and easier reloads which generally necessitates extended magazine baseplates, which in turn adds capacity to magazines.
that help?
You missed the internal oil pump that self lubricates the innards while while shooting. Disum hitek stuff