I have a Mac CAI and I remove it from under the car. You gotta hope that the clamp is oriented so you can access it. The person who had my car before me must have been a midget contortionist cuz I had a time.
My filter is kinda oval so out the bottom was the only way to go. Be careful - there is a shank that sticks out on the fender side of the filter - dont snag the filter.
I repositioned the inlet tube so I can get the filter on and off with the tube all attached (beforethat, the filter hit the fender before it would come off the inlet tube).
Do you have a blockoff plate at the fender (to seal the inlet tube)? I dont have one and was wondering what it looks like exactly so I can make one. Should be fun given the funky contours around the inlet hole.
Good luck.