Here's what I went through with my '01 Navigator just a few months ago and the trucks are really pretty much the same inside.

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At 12yrs old and 215k miles, the 'gator was still running great (it's definitely a Wednesday truck)...but it was starting to look a little tired. So I started planning and ended up doing....

1) Swapped out the Navigator air bag suspension for a full Expedition coil over setup - probably picked up at least an inch just doing that swap.

2) Needed new tires anyway...so....I bought a set of 315/70/17 tires and a new set of 17x9 wheels 4.5" BS.

3) Added 2" coil spacers in the rear and a set of 2" keys from Pro Comp in the front.

4) Plasti Dipped the entire truck in a matte camo green - think Olive Drab / army ... personally, I love it.

Had to do some trimming to the inside plastic part of the running boards and a little on the front part too - neither is noticeable from looking at the truck - you really need to get down in there to see where it was trimmed.

Before:



After:

 

Was this lift with the air suspension? I've seen so many conflicting opinions as to whether you can even lift a 98-99 without changing over from air? I just bought a 99...