I've seen a few people who had Eibach lowering springs give up and get coilovers, claiming that Eibach was good, but the original dampers held back performance. I think this was all people with pre-2017 cars. Are there 2017+ owners with Eibach springs who thought the newer dampers were sufficient? I don't want to waste $ on springs if coilovers are that much better. I don't want to waste money on coilovers if the newer dampers help enough.
They don't really sell a big brake kit for the Mirage. Its one of those companies that will custom make you a big brake kit for most cars. It would be interesting to see if they actually would for a Mirage. You should hit them up and find out.