Two of my splash guards fell off the one behind the main big one then one on my right side in front of the wheel. My buddy said I'm missing the whole wheel well section. And my headlight is out on the same side. When I drive I hear the air and i don't want my bumper to fly off.

I'm bringing it back to where I bought it so he can look but I want all the undercarriage replaced anyone know how expensive it will be ?

what do you mean by "all the undercarriage" ?
I cant see your bumper flying off becuase of missing wheel well liners, but maybe it could?

I picked up wheel well liners from rockauto for like 30 bucks each. i think z1 motor sports has a wheel well liner set too. but i believe z1 only has the fronts, not the backs. as for the undercarriage? i guess that would just be the undertray? not sure on the price of that, i replaced mine with an aluminum undertray

as for your headlight.... could just be a bad bulb

Head light is the ballast they think bulb is fine. And there replacing the fender liner. They zip ties the other ones

may want to look into something more secure than zip ties if your tires is hitting them. i dunno if it was just the shitty rock auto liners, but i zip tied them and the second the tire touched them on a bump in the road, they ripped off. but i dunno if screws would have made a difference.

so the bulb is fine but the ballast isnt? have you taken apart your headlights ever ? or potentially the bulb came loose? make sure to twist the bulb to lock it into place. i took it to a shop when i first got my car and the shop just pushed the bulb in 3 times and had me drive away before one of the guys realized it needs to twist.