What are the differences, only graphics?

Graphics, and a minor bugfix for Bob's Mods compatibility.

How to build X750 and where to get Quantum Waste?

the recipe for the X750 is from the Aerial Superiority tech, and Quantum Waste is a byproduct of creating Antithetical Matter, from the Exotic Oil Processing tech.

X750 can only be build in Terra Tech Assembling Machine.

No? It can be made in any assembling machine, even an Assembly Machine 1, as it uses no fluids. Case in point: https://imgur.com/a/Ah8s6LP

You are wright, I am using one of my favorite mod: "Logistic Assembling Machine" and in it this recepie is disabled.
PS. Check graphics for "ANCT Generator MK3" it has graphic of sync, and I do not know if it is Your intention, but Your warehouses are a bit to big of the top, I know they are big, but even the Reactors or Oil rafineries are in their placemant box to see all aroun them. And I thing Your power balance is off, like power ANCT generators are so expensive to use "World array", and powerfull solar panels but do they have build in battery?
And did You make graphic for the planes? Is it some sort of program to make similar vehicles?

The graphics that extend above the placement boxes are intended, to simulate you walking behind a very tall structure. The recipes are expensive because that's how they are in the high-res version of this mod, this is only meant to be a port of the low-res version for people with lower-end computers. All of the graphics came from the 0.16 low-spec version, or the high-res version for newer things. Go ask the original author if you want to know how to make them.