How can I customize DNN Login & Registration Modules Controls (UI & Behind Logic) .. I want to add additional fields to registration and also the same for login ... I need also to add specific login when the user login or register (Adding & Updating Records in some DB Tables) ..so what is the best way to handle such thing ??

Note : I want to use DNN Login & Registration but i want to merge it with my Application Logic .. So what is the best way to handle that .. Modifying Existing DNN Controls ..Or build new ones ..or any other way ????