Plans are to lift 6" and wrap 35"s 5.4l 4x4 with stock 3.55 gears (unless the offroad package was 3.73?) plan on grabbing a cai and a tuner. Will I really want to regear? Or will it be fine?

 

02+ fx4's had 3.73:1... If that's the case I wouldn't bother for 35s, if ya got 3.55 you can go to 4.10 and get the power and mpg back, but either gearset you're not gonna notice a huge difference just going to 35s... if you got money to throw around then toss 4.10s in and don't worry about it

Pay close attention to how it feels now and put the 35s on and let us know how you feel about the power, I bet you don't notice too much of a difference.

I had 3.31 with 37s and it wasn't that bad, could still spin tire not that I do that a lot but I did maybe twice, and you could only really notice up hill, it would downshift sooner/more often till I installed 4.56s...