Given you are increasing the number of ports, and the i201 is no longer sold, before upgrading I would really look at just going ahead and installing a new platform, the 600r or the 1005r. Also, I just saw a bulletin that there is a new 202i platform that was just released. You would then do a platform migration, either with tape, or as I did mine, over the Ethernet connection.
Last year I upgraded two systems from 2.01, a 200i (a platform that is EOL) and a 201i. I don't know the monetary details but for the disk redundancy we went ahead and put in the 1005r. After having some issues with the first migration causing it to extend out to 4 hours, the second was done in over an hour, along with increasing to 24 channels.
You might check with your vendor to see if there are any Nortel marketing deals that would help you out.