another question would be "will Hasbro include the other 4 cassettes?" Making him much more desireable and also allowing them to charge a higher value.
I think they'd have a hard time marketing the cassettes on their own here. potentially not bothering, unless they do include them with soundwave.

I'm hoping to get the Hasbro release, but in the mean time I'm tossing up as to whether i should pre-order the cassette pairs, just to make sure I have them.