Since you have a green color, might wanna consider clear Plastidip. That way it blends more and doesn't look out of place.
I'm sure Chicago winters aren't as bad but I generally put on my mud guards which help quite a bit with rocks/gravel/salt being thrown up on the sides of the cars. I would probably just hit the parts that generally get the brunt of debris like hood/roof/front bumper and maybe the rocker areas. If you just concentrate on these areas, it will def not cost you $100 for winter paint protection.
Also getting a soft bristle snow brush helps too. Make sure to have some quality paint sealant(at least 2 layers) on beforehand as well.
I've been doing well with Klasse Sealer with Collinite 845 on top for the past few winters.