The only lifts available for the IFS Rangers (98-08) are
Superlift= $1500.
RCD=$2300.
Dixon Bros=$3200.
The Superlift is a drop down bracket lift, meaning that it drops the T-bars and front diff down so the cv's wont bind.
The RCD kit eliminates the T-bars all together and uses coil overs, however in 04 IIRC the Rangers went from a 11.23" brake rotor to a 12" and the kit wont work with bigger rotor, you would have to switch them out for the smaller ones. Several people have done this and said that it still seemed to stop just as good as before. It's also not a bolt on kit, you'll have to have the gussets welded on the shock towers.
The Dixon Bros kit take the RCD one step further by adding better cv's for a long travel suspension, however this kit will require you to have fiberglass fenders with a 3" bulge to compensate for the longer cv's.
Those are the only options you have for a kit, but you always have the option of a solid axle swap (sas) take a Jeep Dana 30(has the same bolt pattern as the Ranger) and fab it all up.
