Hello, Yes I would change the intake also, if you are trying to get the exhaust out faster, you have to bring in the air faster. The stock air filter has too much restriction in it to make that happen, and you will not get much out of just the 4" exhaust. I have a 03 F-350 SD 6.0L, it has 127,000 miles on it. I have a 4" MagnaFlow exhaust turbo back, Superchip 1704, Airaid cold air intake system, I have also added some gauges, Trans. temp, Boost, and EGT gauge, if you are going to do any pulling with your truck, or you are going to chip it, and only want to add 1 gauge, that gauge should be the EGT, that truck running stock is capable of reaching EGT temp's of over 1200deg's and that will blow head gaskets and break or stretch head bolts if you keep your foot in it to long on a long pull. I pull a 39ft 5th wheel trailer that has a 12ft toy hauler in the back, this trailer weights 12,000lbs with nothing in it, once I add every thing in it ( water, gas, 4 wheelers, dive gear ) the weight goes to around 15,000lbs, and I have no problem pulling this rig as fast a I want to go, how ever I do have to watch my EGT temp., it will go over 1200deg's, I do not mind if it goes to 1200 for a little bit, but I do not let it stay there long, I make it down shift and then back out of it a bit and the EGT temp., drops right away. I have had no problems with this truck with this setup on it, and it pulls much better, and has no turbo lag. Hope this helps answer your question.