I always recommend going the OTHER direction. Keep the live site, and add the new settings to it. WAY SAFER than doing partial data copying from the live database. Invariably people miss data and then end up with problems. By always using the main database for your live data you won't lose order/customer or any other related data, nor will you run the risk of damaging the data in transport (such as special characters getting lost/damaged due to charset differences in export/import tools/files, files too big to import and then data gets lost, things missed due to insufficient study of the db schema and wrong assumptions made), etc.
While kuroi's statement is essentially accurate, it leaves out any data related to payment history logging and so on.
.
Zen Cart - putting the dream of business ownership within reach of anyone!
Donate to: DrByte directly or to the Zen Cart team as a whole
Remember: Any code suggestions you see here are merely suggestions. You assume full responsibility for your use of any such suggestions, including any impact ANY alterations you make to your site may have on your PCI compliance.
Furthermore, any advice you see here about PCI matters is merely an opinion, and should not be relied upon as "official". Official PCI information should be obtained from the PCI Security Council directly or from one of their authorized Assessors.