Dale,
we have even another example of work savings, buy the individual parts in individual boxes, vole! Each package is much lighter
However, realistically, when buying an item like a complete rear assemble that will bolt into a factory location it is most likely a good choice from the stand point of price and convenience.
Deal is , for me I have yet to build anything that bolts in
If I am not cutting, grinding, welding it has not been properly modified