Depends on budget, time and skill. More than likely it will fit without too much trouble but it is the ancillaries that will take the most time/money(Engine mounts, ECU, wiring, cooling system, etc.).
It's an automatic gearbox, it will change when it wants. Regardless of whether you change when the light comes on, you will more than likely hit the limiter due to the Aurion gearbox being very slow and docile. Not worth bothering.
"Feel free to create a thread here as well to showcase your car." I don't believe a means multiple.
http://au.toyotaownersclub.com/forums/index.php/topic/31797-welcome-to-tocau-please-read-this-if-you-cant-edit-your-profile/