Hi Patymac, you should get a controller the 700xx runs very lean from the factory I was told they actually qulifiy for Euro 3 emmission standards. Thats why when you open them up they increase HP big time. I have the HMF Bill Ballance system with controller and filter and it was a real seat of the pants upgrade not just one where its sounding louder so you think your going faster.
Regards Overlord