Did you do all these mods at once, or did you see how you thought about the sound after doing each mod? I ask because that is a lot of mods, so is really is hard to assess what is causing the sound to not be to your liking.

Another question, the silicone sheet. Is that for the case? I think you should try removing that if you have not, as I think that will help with the overall sound a bit. I also think that you can remove the tempest mod, as I don't feel this is needed since you have the PE foam on there as well. Using too many mods can make the sound just off because then you have so much going. So removing the silicone and the tempest mod I think is a good place to start.

Ultimately, I think the best way to have done this is to do the case and sound mods slowly one at a time and experiment with different combinations until you found a result you like. There is such a thing as too many mods, as you don't want there to be too much going on inside the case.