Hi, when I bought FCS 5.1 it happened to be a crossgrade. I didn't know what crossgrade was at the time, I recall there were some complications installing it, but after speaking to Apple support it all installed just fine & got registered. I haven't used it for a while, but thinking about upgrading it to current version 3. Is it possible or would I have to get a full version now? Thanks.

You may want to give Apple a call to double check, but unless it'a an academic version, I think that it should be upgradeable.

I also would wait on upgrading until the new Final Cut Studio 4 is announced in the coming 2-3 months.

I also would wait on upgrading until the new Final Cut Studio 4 is announced in the coming 2-3 months.

Unless you need it before then!