1. Yes, you can use them, but I would strongly suggest you use Dell-certified, enterprise-class drives, not cheap desktop/consumer-class drives. 2. They are just labels so YOU can see and know which disk is which size - the carrier itself is the same for all drives; you can peel the 73GB/10K label off. 3. No.
I have a PowerEdge 2900 that I am preparing to reconfigure from Windows Server 2003 to Windows Server 2008 Enterprise R2.  The existing disk configuration is PERC 5i/integrated with two RAID arrays, the first for the system drive (C:) containing two 73 GB disks (one is 73 GB and the other 146 but just using 73) and the second containing four 146 GB disks.  When I look at the "carriers" or plug-in chassis that contain these drives, the system drive carriers say, "SAS 73GB 10K" on the front and the others say, "SAS 146GB 10K."  I want to upgrade the system drives and have two Seagate 500GB drives with which to do so.  My questions are, (1) can I use the Seagates?, (2) What will the system do with them if I place them in the 73GB carriers?  Will the system see them as 500GB or reduce them to 73GB?, and (3) Do I need to purchase new "carriers" in order to use larger drives?  Thanks for any help.
Upgrading Hard Disk in PowerEdge 2900