Question : Difference between Server 2003 Appliance edition and server 2003 R2

Hopefully this will be a nice simple one for someone.
 We have a Dell Powervault 745 connected to a Powervault 220 NAS box, with Windows Server 2003 Appliance Edition installed. We have recently run into problems and need to rebuild the OS, but do not have the original Appliance Edition CD.
 Dell tech support say it may be possible to install Server 2003 R2 but they will not support it as it was shipped as the Appliance edition. So my question is, what is the difference between Appliance Edition and normal 2003 R2? Would we loose any functionality in the upgrade? It runs a basic DFS and Volume Shadowing, nothing too technical. Any advice or light shed on the subject would be very helpful.

Answer : Difference between Server 2003 Appliance edition and server 2003 R2

Windows 2003 was Appliance but I think its now Windows 2003 Storage Server. Its a slimmed down version of Windows desiged to be used for NAS boxes

If you only do BFS and Volume shadow, I don think it will be that matters

but if yo uwant to read, you can go http://en.wikipedia.org/wiki/Windows_Server_2003#Windows_Storage_Server