Thank you for your nice feedback! :-)
In original concept, I was thinking about having unique types of spare parts for all categories that would be used for repairs. But as I was thinking about that system more and more, I thought that it would be little too overwhelming for a player. That is the reason why I decided to simplify it to $ at the end. But I absolutely agree, that some kind of spare-parts management (if made well and ballanced) might add another layer to the game mechanics. I will definitely think about it again in case I will continue work on this game after game jam.