I doubt that the new rotax 915 will be $40k. The 914 is 28k US and the new 915 will be at least $5k more. add shipping, GST and convert to aussie and you will be north of 50k.
Add a prop to deal with the new power, the cost to install it all and you will endup with a very expensive aircraft. A 912s on the other hand makes some sense.