I will buy this. I woun't install it, I would copy some libs and commands over OS3.9 equalents.
Just note, however, that there will be no support if you do not install with the provided script, you are then on your own. In particular, a couple of components depend on each other, as provided in the distribution.
Just to give you an idea: There will be a new queue-handler, and pipe-support in the shell. Pipe-support will not work fully with other queue-handlers, for example when aborting a pipeline with ^C.
Support for the new mount-flags such as DirectSCSI will not work if you do not use the file systems that come with the distribution. For example, FAT95 from Aminet will *not* support this flag, but CrossDos will.
Hence, if there are complaints about "xyz is not working!", then the first question will be "Did you install from the disks", and if the answer is "no", then there will be slicence.
So, you are certainly welcome to install as you like, but do not expect that you get help for solving the problems this may cause. We try of course our best to avoid such problems, but it is not always possible.