Maybe. The M2 kit has a 1.25" intake and 1" output and the S2 kit has a 1" intake and 3/4" output, so you might also need an 3/4" S2 fitting for the output (since the one on the M2 is a 1" fitting). Not sure if this helps.
Does anyone know the answer to this question. If compatible, the Unions would need to be the same between the M2 and S2. It seems to me that it would be bad product design to have the unions non standard between the two pumps.