My wife saw an article on a Super C website about the cabin air filter in the M2 chassis. I checked & it does have one hidden behind the panel on the passenger seating area labeled ' Cabin Air Filer Access'. The panel/cover is secured w/ 3 T20 Torx screws. After the cover is removed a vertical cover plate is visible, & is held on by 6 T20 Torx screws. The #6 top screw isn't visible in the picture because it's hidden by the dash panel. The panel has to be pushed upward slightly so you can insert a screwdriver. The screw just has to be loosed a few turns so the cover panel can be swung to the left side. The filter is on the right side of the opening, & just pull it out. Mine was full of pine needles from where I park the RV, & other bugs & trash.
I found a replacement filter on Amazon for under $10 - some places wanted almost $40 for a filter. Time to do this should be less than 30 min.
I change that filter once per year, it gets really nasty. The air intake is right on top of the passenger side firewall, so a lot of debris etc... goes down into that filter.