I have 4 Drives I plan to put into an OWC Mercury Elite-AL Pro QX2. This will only be a TimeMachine volume. The catch? I just discovered that they are closely spec'd but aren't quite exactly matching. All 4 drives are Hitachi 2TB Hitachi Deskstar 7200RPM However, Differences: Pair #1 are Nov 2010 3.0 GB/s part # 10311 -- 32 MB Cache Pair #2 Jan 2011 6.0 GB/s part # 12115 --64 MB Cache Recommendations....Should I: 1. Use whatever RAID format I want and not worry? 2. Avoid striping them and use them as 4 volumes merely spanned together? 3. Avoid putting them together no matter what?