Its pretty easy.Ive installed about 6 of them and this is the easiest way Ive found to do it.
1)Remove the clamp from thats holding the MAFS to the intake tube going to the TB not the part thats connecting to the stock air box.
2)Now yank the entire air box out of its place. Its not held on with any screws so forcefully pull it out of its holes. Its in there pretty good so dont be scared if it feels like your pulling to hard. For better grip on the box remove the little resonator on the side of the intake. Then the box should come out.
3)Unscrew the 3-bolts that were under the air intake box.
4) Remove the MAFS from the stock air box and bolt it nice and tight to the FS heat shield.
5) Mount the heat shiled down to the holes where you removed the 3 screws and then screw it back in with the same stock screws. Makre sure its nice and TIGHT!
6) Tighten the clamp of the MAFS to the intake tube side nice and tight then attach the supplied FS coupler to the other side of the MAFS and attached the filter with the clamp nice and tight. Install the included black trim and give all the screws one last torquing to ensure there all tight. Done.-Enjoy!