Buying a bolt on kit will solve most of your 'what needs to be done issues' then it would just be a matter of ironing out any issues that come up during installation. I'm not sure if not having the ecu map makes it harder for the tuner to attach (as they need to tap into the right wires for the piggyback to operate, ignition, fuel etc). However, I found an ECU pinout for the ScionTC 2az-fe here: http://www.powerenterpriseusa.net/products/electric/camcon/ECU-data/tC%2007%20Pins.pdf . For the most part the pinouts should be the same but there may be one or two differences (the 1mz-fe pinout in the US is only slightly different to the AU 1mz). So really if you aren't confident tapping into your ECU harness. Buy a piggyback ECU (secondhand is good as you don't care for the harness you get, as there probably won't be a ready made one for the 2az), print out the ECU pinout and give it to your tuner. They'll do the rest.