You got lucky the engine internals are all good! You have a couple options here. First you can replace the plastic balance gears with more plastic gears, I have a new set I need to get rid of that I can let go for $20.
If you plan on racing you need to upgrade the clutch.
The new style clutch kit which comes with new steel gears is $524.48
Or if you don’t plan on racing you can just swap over to the steel gears which are $48.64ea
I would assume there could be some damage to the other gears in the case. They only run the larger two gears as steel and the other 3 remain plastic. I have never had a failure in the balance gear case with the new gears. Check the other 3 gears for damage and see which ones you will need.