On the front other than the splash shield I know of no plugs. You might want to remove the cowl under the windshield and check the area on the passenger side where the door for the A/C is located. The tank for the windshield washers sits behind the splash shield on the right side.

In the rear there is a plug on the forward side, down low near the rocker panel, in the wheel well. Also plugs under the car just aft of the axles. There are two baffles behind the black interior panels. They equalize the pressure inside the car to the exterior. Should be on both left and right. If you remove the small panel to access the light bulbs for the rear lights you can see the black plastic baffles in the coupes. I do not know about the convertibles.