You should have a 3 BAR already with that boost!
You really need to get it setup, the fact there is such a discrepancy in the boost is quite worrying, has yours had a T3 conversion?
There is a mod similar to what you describe, which is affectionately known as "2 stage boost" which sounds rather fancy, in reality it's nothing other than cutting power to the boost controller, this will probably be more sophisticated in your case though, given your controller.
I am not sure on the implications of removing it, does it still run via the ECU or independent.
Martin