On the 3.0 you wont really feel a difference, but on the 4.4i you will. The owner of AFE told me on the phone when I called to confirm the results. He said that he has a 01 4.4i and a 03 4.6is. He told me on the 4.4i he got 10 hp and 20 ft. torque extra ( dyno tested with proof of performance gain) and on the 4.6is, he found almost the same but a little less like 8 hp and 15 ft. torque. Now just by me installing the CAI, I noticed right off the bat! Big difference in take off and at mid range. Its like the car just wants more and more. This is just my opinion. But I also to dynoed the car at diamond performance in Carol Stream IL. and found the same results on my car. So, I guess the owner was right and guarantees his product 100%. I believe him because I had the dyno done for my self. Just my 2 cents. Good Luck buddy.