If our Jeep were in better shape to start with, this is the only part that we would have changed to make the engine run. The instruction sheet included with the engine breaks down which part number Accel injector you need to use by model year of your Jeep. You don’t need an adjustable fuel pressure regulator, an adjustable MAP sensor or anything. Just a new set of six injectors. We actually ordered eight injectors from Summit Racing because the eight-pack is cheaper than the six-pack.