You shouldn't lose power, just make sure to swiss cheese your airbox to feed more air to your engine. I doubt you would notice a loss in power...once you get your programmer it will be a no issue on the so called "loss of power." If you delete the cat, you will throw codes unless you buy a thing called fingerstick (basically a bypass so you don't throw codes)and an EGR blocker plate.......do a search on dieselplace.com.