EAVS is the first generation of SATA II Caviar Green with 16MB cache, EARS is the second generation SATA II Caviar Green with 64MB and 4K sectors (Advanced Format) and EARX is the third generation of Caviar Green with SATA III, 64MB cache and 4K sectors.
For any RAID configuration you need to make sure to use the exact same drives or you risk having a RAID that dies quick or is slower than a snail… Call WD, if the MBSII is under warranty they should help you find the right drive for free.
