Before we first started the car we noticed that the SAFC was registering Airflow.. But while driving around and playing with boost last night a little we noticed that it wasn't registering ANY airflow... we can still control the fuel etc... Any idea's?

You check all the wiring to make sure it didn't come loose and that you have the right airflow setting chosen on the AFC?

we followed the instructions on tuning the SAFC on the main page of 2gnt.com. We have the sensor set at 06in 06 out... I'm thinking it's a loose connection... very possible it came loose while installing the MSD..

How would that affect the car if it doesn't register any airflow on the SAFC?

I'm not sure how they are are setup on a 420a so I can't say I know on a 4G63 you splice that wire and it's what the ECU reads the adjustments on so there would be a problem tuning if it didn't register.