Installed a K&N intake system ( the FIPK tube and filter) and a helical spacer in the throttle body on my 4.6L, about a year ago. Noticeable better engine response, slightly better gas mileage, about 1 mpg better. Recently added a Gibson catback exhaust and this adds to the air intake system to give noticeably better power, and the motor no longer struggles to get into the higher rpm's. This truck has a 5 spd manual, and I can really use the whole powerband now.Overall driveability is better. Gas mileage with the Gibson exhaust stayed the same as after the intake mod, and I can use regular gas, unlike some computer chip setups. The biggest power gain is in the mid to mid-high rpm's, just where you need it for long hills. No noticeable change at low rpm's, but the 4.6 isn't a "grunt" motor anyway.

 

I've put on the K&N FIPK with the 1715 tuner in performance tow mode. Using premium gas gained performance and only about 1/2 MPG. Have the Gibson exhaust on order and will install as soon as I get it. It is good to hear that someone else is using the mods I'm doing and getting good results. I can't wait to get the exhaust in and the camper hooked up. Hopefully my mods help in makeing the trailer puller easier.

 

I have the KN FIPK in my 98 F150 4.6. I also added a set of Gibson headers with my dual in dual out Flowmaster Exhaust. Also no cats. The performance increase was VERY noticeable. It sounds great and has better gas mileage.

 

I installed the following modifications and I only noticed minor improvements.

K&N FIPK, Magnaflow catback, and Hypertech Programmer.

Out of the three mods., the best improvement was the transmission shifting from the Hypertech.

Save your money and take your wife or girlfriend for a really nice dinner. At least at the end of the night you will get some major performance.

 

I put on flowmaster, cold air intake and a 1715 microtuner. I can really feel the difference in the seat of the pants. Next mod will be 4.10 gears front and back.

 

Got the exhaust in. Not too bad, had to deviate from the instructions because my truck was modified by Ford to put the exhaust behind the rear wheel already. One extra cut of pipe. Much quicker throttle response and more power. Happy happy!