I'm considering an intake upgrade and catback system for my 97 Expedition with 5.4. I've read that these upgrades don't give as much of a power increase on the 97-98's compared to the 99-later with the better flowing heads. I tow a heavy trailer (5,600 lbs) and don't want to lose any low-end torque. I also don't want a droan in the cabin since my wife and in-laws ride frequently in the truck. I live in MN and have winters that get pretty cold so will an intake upgrade need to be removed in the winter? What is your experience with these upgrades on the 97-98 5.4 and how do the results vary from the 99-later engines? Have you had any complaints on interior resonance with the Magna-Flow catback? Thanks for your time.