I am not good with plugins, I barely have any idea of the whole programming language thing. However, I want to make a new armour upgrade for Firebats, which will be the same as the Ultralisk's Chitinous Plating. It will go alongside the normal Infantry Armour upgrades. I think it should be rather simple actually, basically requiring a code that goes "if upgrade X is completed, armour of Firebat +2", but I do not know how exactly such a code needs to be written. I also do not want to replace the Chitinous Plating upgrade. Any ideas?

As far as I know, this isn't possible without replacing the ultralisk's upgrade.

Oh, well that's a pity then. Thanks for the answer anyway.