The builtin ROM samples are new or new resampled for use with new stereo S&S engine. The new plugin system can hold new SRX 64MB ROM cards (only for XVxxx) mostly with excellent stereo samples. It can also hold old SR JV cards and has full compatibility with older JV/XP patches.
XVs will not contain "bonus" extras like XP30. That was only a Roland's marketing trick to shell XP parts and cards and hold its customers until XV announcement.