Simon Burtsal and Geoff Williamson are working on an octave divider kit, dunno when it'll be ready. A digital divider can drop polyphonic stuff down, but an analogue circuit can only do one note at a time, meaning the board has to have a circuit for every note in the octave.... like the pedal divider from a T series!!!!
Dzlvs8 used a T series board on his M3, worked well. I used one of Geoff Williamson's OLD boards, which cost a ton on parts.
There's also the Kon Zissis mod where he takes your M3's pedal tonewheels, filters 'em to clean sines and whacks 'em onto the lower manual. Note that the lowest manual octave goes from F while the pedals are from C... so there's a bit of juggling up and down to get them to fit. Apparently it sounds okay.
Do you want the recipe for that one?