Solution
[External] X-Crash is a third party software tool developed by [External] MeasX, meaning that NI cannot provide a detailed breakdown of it's capabilities or a side-by-side comparison against the DIAdem Crash Analysis Toolkit (CAT).
X-Crash is based on DIAdem CAT, but is intended to be a turn-key solution for analyzing vehicle crash data that is in line with pertinent standards. DIAdem is a more wide-scoped tool that is not specifically designed be be crash test accreditation compliant. Attaining the same capabilities as X-Crash using just DIAdem CAT would require extensive customization of DIAdem and an in depth understanding of scripting.
For a list of analysis functions included with DIAdem CAT, refer to Crash Analysis: DIAdem Help. [External] Contact MeasX for more details about X-Crash.