Gregory's Ford in Canberra is offering a an emission treatment service for $98. The treatment is meant to clean the complete fuel system including injectors, fuel pump, fuel lines etc. It also cleans the lubrication system, sump, oil pump, oil galleries, valve lifters, piston rings etc.

Has anyone ever had this sort of treatment done? and is it worth the money?

It sounds to me like they'll put a bottle of injector clean in the fuel, and oil flush in the engine, run the car, change the oil and give it back to you.
Because a proper injector clean will set you back about $200ish.

All engine oils have detergents and dipersants in them to clean the engine. That's one of the functions of oil.

1. Lubricate
2. Cool
3. Clean

If you do regular oil changes, the oil system won't need a clean. If you don't do regular oil changes, you can get oils which have kerosene in them to de-sludge the engine. They are good at cleaning a neglected engine.

Or, you can just run normal oil and change the oil every tank of petrol for a few tanks. That will also clean out the engine.

It's just a way of getting $98 from people and not at all worth your money.

So, regular oil changes keep your enine clean, and running all the time, or even every 4 or 5 tanks, on Optimax, Ultimate or 8000 will keep your injectors clean as all those petrols have cleaning agents already in them.