I worked in shipping and receiving for a few years and I can tell you that for the most part, it's the packaging. Granted there are times when it's just UPS' high speed sorters fault, but mostly it's just the fact they used a weak box and/or didn't pack the items good enough.
If I were to be shipping something like that, I would stick with FedEx, the packages from them are usually intact without any damage, UPS, it's hit or miss.
96 ZJ 4.0
04 TJ 4.0
87 Rx7 TII