[Karaya]

The E-7/Z was a very limited variant featuring the GM-1 boost for high altitude.

The E-7/N was ftted with the DB 601N engine (instead of the DB 601A)

Actually the E-7/Z was also to my knowledge equipped with a DB601N so Oleg's ingame model is inaccurate as it still has the DB601A under its cowling!