You will have the harness thats came with the emb which will be igniton and fuel harness to be hard wired into the stock ecu wiring. The zisco one will be a field harness so you dont have to wire it to the stock ecu wiring it will go to that or if its a plug and play harness no wiring at all imo they are a waste of time when are you ever going to remove the ecu after its mapped ? cheers nick. http://www.boomslang.us/e-manage-blue.php thats a proper plug and play harness zisco one is like a said a harness to wire your 2 harnesse to http://www.ziscoperformance.co.uk/index.php?main_page=product_info&cPath=11&products_id=36