Certain VDL:2 instruments come with "lite" and "full" versions. On the surface, nothing is different about how these instruments function. The main differences lie beneath the surface where less velocity layers are used in the LITE instruments and decay times are generally shorter by default.
Using LITE instruments is a good practice when working on intensive scores with several tracks. When it comes time to record, you can swap the FULL and LITE instruments for added detail without worrying that the keymappings won't match up. They are completely interchangeable. Essentially, the LITE versions will place less burden on your CPU and will use less RAM, so you'll gain better performance during the day-to-day process of writing.