damn, where were you a few months ago !
i had a buttload of parts for the gen5 camry !
i had Fortune Auto series coilovers made for the car, custom made the first run in the early 2010s pretty cheap too ! iirc it was around $1400 almost the same as the entry level BC coils during that time, but much much comfier . PM me i think i still have some of the strut top measurements (which is needed if you were to get coils from other years)
you will definitely have trouble with coils as the aussie gen 5 camrys (xv36 vs the normal xv30 chassis code - keep this in mind) use the gen 4 chassis, (98-02) (xv20), so if you want coils, best look for those years, in fact even up to gen 3 (xv10) fit.
stock toyota ECUs are tuners worst nightmare, they wont be able to do much to it. As mentioned yes, a full standalone ecu will open up the tuners options, but as you can see, it comes with a price tag. So if you were to do some ECU upgrades, you may as well go supercharger.
any further questions, dont hesitate to PM me,
-jeffy