I don't think that thread is going to inform anyone of anything very much 
The important factor is balance within the suspension system, and yes uprated front ARB's and rear ARB's can make a large improvement to the car's handling when blended with all the other components and setup by someone who really knows what they are doing.
If you consider changing the front ARB, sticking a rear one on and nothing else you are far more likely to throw the car out of balance than improve it, despite the flatter cornering fooling the arse dyno it's a big improvement.
The rear ARB is used to finely tune a near perfect setup and will not cause the unwanted handling tendencies mentioned in the thread.
If you are informed by the garage that it will, or has when they tried it you probably need to go somewhere else to get your car set up.
