Should I use the shield you can buy separately or not? I live in Kansas so it rains every now and again but I rarely drive through rain. Also not sure about car washes but I could always just wash it myself. Do you guys think it would affect the performance of the cai?

 

I would, It doesn't hurt the performance and will make sure the filter isn't soaked, in the rain or when you wash the car. Better to be safe.