Depends what matters to you the most.
Mojo classic is capable, can drive EDXS . EDXS is Sundara on steroids, just about everything is more and better.
EDXS is also better at imaging! and here is where you would benefit from M2. Also bass definition is better on M2.
M2 other facilities (EQ, crossfeed etc.) were wasted on me, but you may really need them.
If I were you, since you just got your Mojo, I would get the EDXS , since it hardly requires any EQ, I would sell the Sundara and save for M2.
Now if you could stretch to a used Hugo2 ......