Hi Zemmuonne,
I apologize for the long wait on this reply... I think the post got overlooked. I use HDRI a lot to light my scenes in Brazil for Rhino. To my knowledge the entire dynamic range is imported and the multiplier value is the main control for the intensity. I have also asked for further clarification from Andy LeBihan who may know exactly how we are importing these files.
When you mention "boosting the RGB level", do mean the saturation level? This is available in the output adjustment section for the HDR after loaded into a GI environment. There is also control there for clamping the range.
bj