well. I'll try my best to answer
1) rereading the latest battle report, it is said to be too havy for use in trenches and too inaccurate for the mountains. their rifle as it is now seems to actually only be rather useful in the jungle, but it could change with improvements in accuracy and weight. Perhaps not as good as I originally thought.
2) I would need to check their thread and see their rolls to have a better idea, but at a glance I guess that even with our superior experience we might not be able to get anything substantially better. What did they use the revision on? if on the rifle, then it means that we have a decent chance of screwing it up by dedicating only a design phase.
3) in the scenario you described, the following things happen
DISCLAIMER: this assumes we don't get to exploit mountans quickly. ground prices don't change from the scenarios described, but our aircrafts wouldn't increase in cost. But since we need to build a road to harvest from their mine, and after that they can deploy vehicle in the mountains as well... I am not betting on us ever seeing that ore.
Arstotzka-Ground vehicles
AS-MV21-AL becomes expensive
AS-T25 becomes manhattan project-level, Very expensive due to resource use alone. Good luck fielding one.
Arstotzka-Aircrafts
AS-A19C becomes expensive(not that we are still using it)
AS-DB-HF-23 becomes Very expensive
AS-HF-24 becomes National effort, unless we cheapen fuel injection in which case it stays Very expensive
Moskurg-weapons
M1 Stallion becomes very expensive (expense from resources, plus I read it still is complex)
Rhino Recoilless Rifle becomes expensive( I don't think that will significantly change their deployment)
B2 Destroyer becomes very expensive (their new heavy artillery)
MK-47 Assault Rifle becomes expensive
Moskurg-Ground vehicles
T1 Smasher Mk II becomes very expensive
T2 Breaker stays very expensive ( this is not a change, but I think it is significant to point it out)
Moskurg-Aircrafts
M3 Wasp Fighter B becomes very expensive
in this scenario(assuming a failed revision on our tank engine) we might keep air superiority , but our ground attack capabilities will be significantly impaired. They lose a bit of general effectiveness and outdated tanks, but get to keep their heavy armor, which is our main problem, while at the same time we lose ability to deal with it. We also lose our armored car numerical advantage, which is also going to harm our anti-tank abilities.
With a partial engine revision ( fuel injection) we surely get air superiority, but we still lose the war on the ground badly.
with a total engine revision our tanks should match their and we should stop their advance.
AS-MV21-AL becomes expensive
Arstotzka-Ground vehicles
AS-T25 becomes manhattan project-level, Very expensive due to resource use alone. Good luck fielding one.
Arstotzka-Aircrafts
AS-A19C becomes expensive(not that we are still using it)
AS-DB-HF-23 becomes Very expensive
AS-HF-24 becomes National effort, unless we cheapen fuel injection in which case it stays Very expensive
no change in the moskurg weapons obviously
with failed engine revision, we lose air superiority, we lose armored car advantage, we can't field armor and we have only artillery to shoot down their. In this scenario we are going to lose the plains QUICKLY.
with partial engine revision, we might keep air superiority, or at least contest their superiority enough to avoid too heavy bombings. forget us doing any bombing. still screwed on the ground.
with total engine revision, air superiority is still at best a stalemate, ground situation improves but since they have the full use of their artillery I think they have the edge here. their cheap assault rifle will serve them well in the jungle as well.
No change in cost to our equipment, clearly
Moskurg-weapons
M1 Stallion becomes very expensive (expense from resources, plus I read it still is complex)
Rhino Recoilless Rifle becomes expensive( I don't think that will significantly change their deployment)
B2 Destroyer becomes very expensive (their new heavy artillery)
MK-47 Assault Rifle becomes expensive
Moskurg-Ground vehicles
T1 Smasher Mk II becomes very expensive
T2 Breaker stays very expensive ( this is not a change, but I think it is significant to point it out)
Moskurg-Aircrafts
M3 Wasp Fighter B becomes very expensive
We get to enjoy unmitigated air superiority and there is nothing they can do about it besides sending biplanes.
we probably resume advancing in the jungle, since the 2 things which stopped us ( artillery, assault rifles) were just made more expensive.
with a failed engine revision, we are still outmatched on the ground, but our air advantage might allow us to mitigate this problems thanks to dive bombing. A general loss of effectiveness means we have a good chance of repeating the miracle that allowed us to hold in the plains.
with a partially successful engine revision: Arstotzka rules the sky and they can't even launch a paper airplane without it being shot. wth dive bombers able to focus on bombing alone, their armor is less of a concern and we are able to produce our own as well
with a successful engine revision we can finally field our tanks in great number and we rule the sky. they jungle weapons are now expensive. In this scenario, we are set for big victories on all fronts.
Why are you looking here? nothing has changed in terms of resources
failed engine revision: this is happening now, you can see the results.
partial engine revision: air superiority, we can field tanks. shouldn't be bad.
successful engine revision: air superiority, we can field tanks in great number. I think this goes well for us, our more powerful and numerous tanks should gain us an advantage