Hey fellas

I have a S1 but havent got an lsd in my gearbox and as S1 boxes are quite difficult to source i was wondering if S2 complete internals will fit my gearbox casings ?

I know that the gearbox casings and crown wheel on S2 is different this is why i ask if its possible

I dont want to have to go down the rute of an atb due to the cost though i would love one !