Replacement is straight forward.  You should have no problems following the procedure.  Remember that after you replace both modules, you need to commit them before they can be used.
I would like to replace my 1GB i/o module with 10GB.  I plan on following the replacement procedure and replace the i/o module on each SP one at a time.  Is there anything that I am missing?
Upgrade I/O module VNXe3300