You might consider re-positioning the airdam to even with the leading face of the bumper.And then wrap the airdam around the corners of the bumper all the way to the front wheels as you see done with modern cars.
Allowing any air to get under the nose will cause front lift if it can't bleed around the sides.
If you wanted to go deeper,you could create a fascia which would modernize the nose,enclosing more naughty bits.
