What territorial and economic changes promoted German unity?

Answer 1

I assume you are referring to the unification of East/West Germany?

Then the most significant demise is the economic collapse of the USS R's money producing segments "capitalistic" versus the " socialist" State's ability to spend itself into complete bankruptcy was the most dramatic change that took place.

As this is true if your answering the question they asked it is.....

That the greatest territorial change was actually Napoleon who made great changes in German speaking lands. Which then of course caused issue and then after he was defeated the problems did not stop. The greatest economic change which promoted unity was the creation of Zollverein an economic union.