Yup, he’s working on it.
I’m not too sure the air filter is that different. From what I can tell, they are basically the same, just turned around. The M54 only has one hose going into it, and another coming out the front to the intake. The M809 also has only one hose in and none coming out the back and the intake on top. The M54 part can easily be modified by smoothing off the front and adding a smaller disk on a pipe on top to be the M809 filter and intake.
M54
M809
