DIY speaker kits typically include all the necessary components to build a set of speakers, including the drivers (woofers, tweeters, and sometimes midranges), crossover components, and cabinet hardware. Some kits may include additional optional components such as grills or finishing materials. In general, these kits are designed to be self-contained and do not require any additional components to function. However, it is possible to modify the components or incorporate additional components into a DIY speaker project if desired. It is important to carefully consider the compatibility and compatibility of any additional components with the rest of the system to ensure proper performance.