Dagger 1.x (which we currently use) certainly helped slim down code size but it's mix of compile time and run time injection made using tools like Proguard a bit messy. We haven't made the jump yet but it seems like Dagger 2.x solves for this: https://github.com/google/dagger
Butterknife is just plain useful to avoid a ton of view boilerplate code.
Our app is admittedly not too complicated but so far we haven't seen any performance issues.
Butterknife and Dagger both use compile-time generation, so they're basically free and make your app well structured. I really wouldn't avoid 3rd party libs in your position, using good ones will make your apps less buggy and will let you easly create way better UX for your users.
For example, EventBus (or Otto, both do the same thing) is pretty essential for coupling things together and keeping them working over orientation and other configuration changes. I've seen so many apps locked into portrait position just because devs couldn't figure out how to decouple model from views and keep the app running over orientation change.