I have the old style ACS splitter with integrated undertray and servicing it is a pain. I found a method to make mine servicable by using rivnuts in place of the rivets. The rivnuts are just rivets with a threaded hole so they can hold onto the bumper just like rivets but with the benefit of being able to use screws. M4 size worked the best for me with a 16mm long hex screw and 16mm washer. I would honestly recommend using a rivnut/jacknut over a rivet as it makes future servicing much easier than having to drill out rivets each time, especially since its a consumable part.
I have the old style ACS splitter with integrated undertray and servicing it is a pain. I found a method to make mine servicable by using rivnuts in place of the rivets. The rivnuts are just rivets with a threaded hole so they can hold onto the bumper just like rivets but with the benefit of being able to use screws. M4 size worked the best for me with a 16mm long hex screw and 16mm washer. I would honestly recommend using a rivnut/jacknut over a rivet as it makes future servicing much easier than having to drill out rivets each time, especially since its a consumable part.
Great presentation on your under tray system. If I have an issue with my Stage 2 splitter and OEM under tray, I will replace it with the ACS system.