Is it overpowered? Not really, they're about as strong as the default spidertrons with their rockets. They don't run out of ammo as fast as rocket spidertrons, but the Tesla ammo has to be shipped in from Fulgora.
If you have another mod that adds enemies on Fulgora, these spidertrons might be a good option, since it's hard to make rockets on Fulgora - there's no local coal or sulfur for explosives.
See also:
