encl id depends on where you are going to place them on the bus, i would try to balance them between the available buses. Hopefully you have long cables that can stretch between the two racks.
Be careful using disks from the old in the new DAEs with exisiting disks. You need to make sure that you are not mixing 4G and 2G disks or you will need to downgrade and that is probably not what you want to do.
The disks to be moved are all 300GB FC 4Gb/s 15k in DAE3P. I've destoryed Hot spares,Storage Groups, Luns, meta luns, private luns and all Raid Groups. the disks are all in UNBOUND state on CX3-80.
Hope we can move the DAE's on to CX4-960 and use NST/USM to connect the DAE's.
Just a closing note on this topic. The CX4-960 can utilise a lot of system cache, up to about 10GB for Write cache, but there is a requirement that the disks and DAE's on bus 0 enclosure 0 must be running at 4Gb in order to utilize the maximum cache. If the bus is running at 2Gb, then the maximum Write cache is limited to about 8GB. This is due to the time required to dump cache to the vault in case of a SP failure. At 2Gb bus speed, you can't dump 10GB, but you can dump 8GB before the SPS batteries run out.
This is covered in the latest Best Practices for R30.
EMC CLARiiON Performance and Availability Release 30 Firmware Update Applied Best Practices.pdf
Just for the sake of completness, the maximum write cache in CX4-960 systems with DAE0_0 running on 2 Gb/s is 6GB (and not 8 GB). The correct number is mentioned in the document that Glen referred to.