Update?!
Not really, done nothing to the car. Still drives, engine makes noises but still living cheerfully.
Bought wheels for this car. No fitment pics yet as car is still 4 stud, will swap over to 5 stud when I get tires on the wheels.
The XR4's are off the corolla, pulled the diff out, took it to machinist to inspect the sidegears which the diff guy was upset about. Machinist says the cusco's sidegears' splines are looser than what he'd make but not as bad as what holden/ford(mass production) diffs are and things will be fine even though it is looser than a factory centre's fit.
Gearbox out sometime this week to fix the leaking rear main, make some fuel lines, put it back together and hopefully driving some time soon.