Welcome
If you can prove that you've owned the vehicle for 12+ months, you are able to import the car without compliance and so forth. However as its in your mums name im not sure of the procedure, or if that loophole exists. Otherwise you would unfortunately be unable to import the car as its too highly modified, and that I don't know if R32 GTS25 are on the compliance listing.
R34 GT-T go upwards of $30k AUD, depending on spec.