I don't know how CL does the upgrades but with Operating systems such as Windows, when you buy the upgrade it is more or less the same as the full version except the EULA is different and it checks for a prior version for whatever it is upgrading. What I am trying to say is that if when you get P6 and install it, if it does not ask for the disk for the original and, this is the big thing, if it does not say that you must have a prior version in the EULA then you can give it away if the prior versions EULA says it can be transfered. Someone at CL will tell you no but as long as the EULA does not say that you cant then you legaly can. If you do give it away then they cannot upgrade because CL asks for the serial number before ordering it as you might remember. Just remember to drink lots of caffene before reading the EULA.