VNX5300 LUN migration

We have a VNX5300 block-only array, which is housing several LUNs. Recently we have had some user complaints regarding a slowness problem with a system we will be going LIVE on soon. I discovered the server is sitting on a thin LUN which has compression turned on (Medium rate). It is also a SQL server which is getting a lot of use currently due to prep work for GO-LIVE. From what I have read, I think the compression could be affecting the server performance.

This is the only LUN with compression turned on for the entire array. I did not setup this VNX so I am not sure why compression is turned on. 

My question is, would it be okay to setup a new LUN (compression NOT on) to migrate the compressed LUN to? 

Do the 2 LUNs need to be the same size, per https://community.emc.com/docs/DOC-52120  ? If the answer is yes, won't I have a problem with sizing due to the LUN currently being compressed and then it will take up more space being uncompressed? 

Also, do I need to decompress the LUN before performing the migration?

Thank you for any help you can provide, as we unfortunately have hardware only support on this array.