Uggh yes removing the grill shutters is one of first mods people do to their Focus ST. They even put them in front of the intercooler. Yeah lets go ahead and just defeat the purpose of the intercooler with these grill shutters. I ripped mine out awhile ago.
On the Focus if you take the grill shutter motor out, it will throw a check engine light. So most people remove the shutters but leave the motor plugged in to keep the engine light off.
On the Focus, the shutters are pretty flimsy and you can just take each one in your hand, bend it down in the middle and it pops right off the track. There are like 12 total, 6 on each side. It literally took me all of 40 seconds to do this.
You may want to check the Dart forums and see how everyone is removing theirs.