I'm trying to understand what modifications can be done to the "bumper" area of modern cars.

At the end of this post I have quoted what I believe are the pertinent sections of the rulebook, and boldfaced the text that I think applies directly.

Question 1: If you have a modern car with non-metallic exterior bumpers that hide the rigid bumper structure (an "integrated bumper assembly", per rule 17.1.4.D.8.B), and this assembly has foglights mounted in it (are they "in" it? or "on" it? See 17.1.4.D.10.g), can I remove the foglights in order to install brake ducts, so that I don't have to make any changes to the body? (See 17.1.4.D.6.B).

Or, do we interpret these foglights as being "in" the bumper, in which case I cannot remove them, but I have to tape them? In that case, I'm not allowed to make changes to the bumper (6.B), or am I (8.B)?

Question 2: 8.b says that dealer-installed air dams may not be installed, but then it says that for "integrated bumper assemblies", airdams may be attached to the bumper cover. Does that mean that I can have a home-made air dam attached to the bumper cover, but I can't use a factory-optional air dam that attaches to the bumper cover?

I suspect that a lot of my confusion comes from the lack of definition of terms:
"in" vs. "on" for the foglight's relationship to the bumper
"body" for the 6.b rule
"front valance" for the 8.b rule

I have a feeling that these rules were really written for when every car had a steel bumper mounted externally to the steel body, and there wasn't any plastic. It's very confusing when I try to understand what the rules are for "integrated bumper assemblies."

The rules (under 17.1.4.D):

6.b: "Air ducts may be fitted to the brakes, provided that they
extend in a forward direction only, and that no changes are
made in the body/structure for their use."

8.b: "A front spoiler/air dam is permitted. It shall not protrude
beyond the overall outline of the body when viewed from
above perpendicular to the ground, or aft of the forward
most part of the front fender opening. This body outline does
not include bumpers or bumper mounts. The spoiler/air dam
shall be mounted to the body, and may extend no higher than
four (4) inches above the horizontal centerline of the front
wheel hubs. It shall not cover the normal grille opening(s) at
the front of the car. Openings are permitted for the purposes
of ducting air to the brakes, cooler, and radiator. Dealer
installed or limited production front/rear spoilers/air dams/
wings are prohibited. The spoiler shall have no support or
reinforcement extending aft of the forward most part of the
front fender wheel opening.

NOTE: Integrated bumper assemblies are defined as those
designs where an external non-metallic bumper cover
completely encloses the primary energy-absorbing bumper
and where this cover could be installed in its normal position
with the underlying bumper removed. On cars with integrated
bumpers, the front spoiler or airdam may be attached to the
bumper cover.

Where an air dam/spoiler is used, two total openings may
be cut in the front valance to allow the passage of up to a
three (3) inch diameter duct leading to each front brake/rotor
assembly.

Where no air dam/spoiler is used, two total openings of a
maximum size five (5) inches by seven (7) inches maybe cut
in the front valance so that brake ducts can be added with a
three (3) inch diameter hose leading to each front brake/rotor
assembly."

10.g: "Exposed headlights, parking lights, and side marker lights
shall be taped. OEM light assemblies mounted on or below
(but not in) the bumper shall be removed."