Camry e153 internals fit in a mr2 e153. S54 being a different case, I dont imagine will work. The S54 is lighter and said to have better gearing for n/a engine.
To do the Camry e153, you need the e153 mr2 case and selector shaft (no longer available and I have tried many machinists to replicate and said no can do), preferably final drive, and oil pump.
To use the e153 Camry case, you need the front engine mount case component ($100), machining of the selector ($200+ depending on machinist) and the mr2 e153 items above being not available/cost too great.
Get the gearbox quoted by a professional, could be something’s small to something big... then make a decision.