Here's a suggestion of how you should block your lower grille:
The green areas can be covered permanently, since they don't play a role in cooling. If you have fog lights in those corners, then just block what is closer to the center. The red area is in front of the A/C radiator, this block should be either removable or openable. You can also make an openable IC block, which would close when the engine is warming up. The blue lines show how the intercooler should be walled off, so that cool air is channeled only to the IC, without contaminating the rest of the radiator and/or engine bay.
Here is a picture of how I walled off my IC from the radiator.
Mike, why is there a silver tube going across your radiator (above and next to the fan)? Does that take intake air from the lower grille to the airbox? Maybe shortening it would be better, like to the top corner of the upper grille. I believe that the stock intake is at the top, correct?