Hi,
Superior 2 sees the same MIDI files as EZdrummer 2, so no problem there. Myself, I find it is quick and easy to get a song structure ready more or less as I want it with EZdrummer 2 and then I switch to Superior 2 for tweaking and drag the MIDI from the EZdrummer 2 Song Track to my DAW.
Alternatively, I load both plugins and feed the MIDI out from EZdrummer 2 (with no or few sounds loaded) to Superior 2 with the drum sounds I intend to use in the project loaded.
There is no cross-grade from Superior 2 to EZdrummer 2 unfortunately, but if you keep your eyes open, there are very often special promos to be found both online and in stores.
Right now, there is only the 'Buy EZdrummer 2 get 1 free EZX' promo in the Toontrack web shop, which may not be what you were asking for.
In the Groove Browser, you should have a User MIDI entry; this is where you can store your favourites or your own MIDI files. It can be accessed in the Finder/Explorer via the Help Menu in Superior 2.
BR,
John
