Not sure if you're quoting the price EACH or for the pair ??
That's about 170 UK Pounds. I recently saw all 4 of these modules for sale on eBay for around 240 UK pounds the lot.(about 432 AUD)

Some of the new sounds are quite good, however you need to be aware of the following......

If you use any of the sounds from the modules in a sequence and give that sequence to anyone else with a KN7000, they will not hear the sounds from the modules, unless they have the same modules installed in their KN7000.
The nearest 'Standard' sounds will be substituted on a KN7000 that does not have the same modules.
This will also apply to your own recorded sequences, should you decide in future to remove the modules from you KN7000.