Welcome to the site!! I'm sure you'll find anything that you need or want to know right here!!
Well, about your question. Since you have a 98, you are in luck. Trailmaster has a 4 inch suspension lift for 98 - 01 Explorers. The kit is a bit pricey, I think I've seen $1400 on the boards somewhere. I think there has also been talk of Superlift making a 4 inch lift for 98+, due later this year, but I'm not completly sure about that.
Little trouble with the Trailmaster:
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98 Sport with the Trailmaster:
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If that's too high for you, then you may consider a torsion bar twist and longer rear shackles or add a leafs. This lift could be a DIY job if you wanna try it and it is an inexpensive way to get about 1.5 inches in your case. (Shackles about $40, add-a-leafs about $60; torsion twist - free, not counting the front end alignment).
Torsion bar lift instructions:
http://www.4x4central.com/torsionbars.html
You may also want to read through this thread. It's got plenty of useful info in it:
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As far as body lifts go, you can use one for a newer Ranger, or an old Explorer. Folks around here have made both work on newer models. These are also relatively inexpensive, and possible to do yourself.
I hope that this helps you. This site has plenty of threads on it concerning lifting newer models. If you try a search, i'm sure you'll get a bunch of them. Good luck, enjoy your truck, and once again WELCOME aboard!!!