All the hardware is included with the slip on. No gasket neccessary. You will, however, need to remove the tail piece to gain access to certain bolts for mounting. Also check the clamp where the mid-pipe attaches to the cat: some exhaust leak may occur and you'll have to fidget with the clamp to avoid any exhaust from leaking out. Installed a Leo on my 08 with minimal issues. Hope this helps.
"I plan on living fast and dying young!"