Actually I'm looking for the possibility to replace IE wires completely with IW counterparts for unification and simplification, so I wonder if there is the possibility to add IE-styled transformers in this mod?

Ooh, that'd be neat. It'd be even better if it looked like the IC2 transformers, but was shaped like IE transformers. Like a wooden box with two connectors on top, for LV, or a red-and-white patterned block for the HV-transformer.