$476 to assemble an 8 3/4 diff

"Years of experience"??? OMFG. Sounds like somebody's skeered of learning..

Some folks would rather have a known cost than fund an ongoing educational/r&d project. This is a hobby for most; only a few of us have the sickness. Everyone must draw the line somewhere. Think of that before you go all OMFG on the poor guy lol.