There is virtually no Japanese performance workshops in Perth who do everything in house.
XSpeed, Hyperdrive, Top Racing , CRed, Speedworks, Ovaboost , In Tune all outsource the head work and engine machining.
All the above workshops then assemble the engines in house to there own specifications which vary with each shop.
The engine machining and tolerances supplied by the workshop is one of the critical factors in engine life and building one to go racing and will be refreshed after every season is different to building one that is in a street car.
The only shops that machine AND build engines are very limited , both in quality and there desire to involve themselves in turbo cars. Most of these shops deal with V8's such as Kostecki, Kendrick, Repco, Veems , Performance Automotive plus others I can't remember.
Cheers
Ken