1. Make sure to keep a back-up, just in case! 2. You can leave EVERYTHING, the new DriverPacks BASE will automatically detect files and changes from an old slipstream, then it will delete them (or restore the original files) and slipstream the new DriverPacks. There's only one caveat: if you have used nLite AFTER the DriverPacks, or if you have made any changes to the dosnet.inf, txtsetup.sif or winnt.sif files, they will be lost!