Personally, I wouldn't bother with any of them. I'll explain.
If you use Optimax, you won't need the injector cleaner as, the Optimax will keep these clean for you.
If you have a decent air filter, you won't need the intake cleaner as it shouldn't be dirty. If it is, just wash the intake pipe and intercooler with petrol. Cheap and will do a better job !
The cooling system flush may be a good idea to remove sludge build up etc.. but, be careful with how potent it is, if you have an old rad on the car. What you could do is re-fill the system with a heavy anti freeze concentrate. Drive it for a day then empty it and re-fill as usual ?!
Colloing system conditioner ??? What does this do ?
And tfinally, if you change the oil regularly. every 6000 miles, with good quality oil, the engine flush will be a waste of time as all it is, is a very thin oil that is designed to wash deposits away. The engine oil will do this par for the course ! I have used this in the past and have seen no benefit at all !
Hope this helps.
Paul