In 50 years at this, have not found a single what I would call a tweak that works, but am not one to try many of them. Recommend buying from vendors that offer good products upfront, why buy stuff that needs fixes? Most tweaks are a scam, at best they do nothing, at worst they impart a coloration. If the tweak is such a good idea why wasn't it incorporated into the original design or in all similar designs?
Tweaks can be tempting, but best to focus on the essentials. A simple synergistic system consisting of solid gear that fits your tastes/room is best. Extra bits just distract and confuse. Don't ignore room effects (weird shape, too small for chosen speakers, limited access, little isolation, poor setup, etc.) as most do. By solid gear I mean that you should look into the company behind the components (service, history, deep R&D/manufacturing resources, reputation).