I will bring back some old discussion here, as atledreier's car is a good example.
His car config may be reproduced on RB4, and it should work as it is, but in lfs is also front/rear power bias slider, which affects torque deliver.
I don't know how, and I don't know what device could change that Mazda, to LFS way of diffs working.
Any advice? If no, I think 4wd systems should be cleared up in lfs.