X360ce.ini - (Configuration) - Contain Library settings (button, axis, slider maps). X360ce.exe - (Application) - Allows for editing and testing of Library settings. Xinput1_3.dll (Wrapper Library) - Translates XInput calls to DirectInput calls - supports old, non-XInput compatible GamePads. NET 3.5 installed anyhow as quite a few XInput titles utilize.
The full DirectX Redistributable will always install the file, however it's best to have.NET 2.0/3.0/3.5 is installed and skips the Managed DirectX framework if it is not. NET MUST be installed prior to the DirectX webupdate as it checks that.
NET 3.5 from the above link, and Windows 8 users can enable it in Programs and Features - Turn Windows Features on and off.