The audio crackling and lagging you have described can be fixed by using the proper audio plugin. The one that comes with the emulator won’t do, there are better ones. And the low res high res switch problem definitely sounds like you’re using an incomplete texture pack, or your emulator isn’t loading all the textures. (Which can happen for a variety of reasons). Sometimes the models do still look a bit odd, but overall with the right texture pack the games on my setup look great in 1080p while still having the same look of the original game.